What emotions is Langston Hughes trying to evoke in "The Negro Speaks of Rivers"?

As a preface to his poem, "The Negro Speaks of Rivers," Langston Hughes wrote,

I had been in to dinner early that afternoon on the train.  Now it was just sunset, and we crossed the Mississippi slowly, over a long bridge.  I looked out the window of the Pullman at the great muddy river flowing down toward the heart of the South, and I began to think what that river, the old Mississippi, had meant to Negroes in the past--how to be sold down the river was the worst fate that could overtake a slave in times of bondage.  Then I remembered how Abraham Lincoln had made a trip down the Mississippi on a raft to New Orleans, and how he had seen slavery at its worst, and had decided within himself that it should be removed from American life.  Then I began to think about other rivers in our past.....

"My soul has grown deep like the rivers," Hughes writes in the last line of his poem. And, this seems to be the controlling metaphor for this poem.  The Negro is from the ancient source of life, symbolized by the Euphrates; he has lived by the Congo and the great, long Nile as well as the mighty Mississippi River.  There is a richness to the black experience expressed in lines 4-7 in which these rivers are mentioned. Hughes use of repetition serves to give this experience continuity, as well.

The black people will survive because their souls have grown deep over the centuries and they will continue to last, just as the rivers have.  Langston Hughes poignantly reminds many of the disenfranchised in the United States of their rich and lasting heritage so that they will remain strong.

Discuss the use of contrasting characters in A Midsummer Night's Dream.

As far as contrast goes, I'm with janeyb here--the most noticable thing is not the contrasting details in most of the characters as much as how interchangable the main characters are. If there is contrast, it would be in the "exemplary" characters--the Duke and his intended, the fairy king and queen and (ok not exactly exemplary...) Pyramus and Thisbe. Titania and Oberon, as faerie royalty, might be expected to peacably woo, but their marriage is fraught with power struggles and strife. When they finally do make peace, it is not out of absolute free will, but as a result of Oberon's trickery. In contrast are the "happy" couple Hippolyta and Theseus who met in battle (Hippolyta was an Amazon Queen before Theseus conquered her people and "won" her). She may be engaged to him but, nonetheless, she remains a spoil of battle.

Finally, Pyramus and Thisbe are the staged representation of lovers who love truly for the time they have but end tragically. And, as the players are wont to point out, they are not real.

These exemplars of mature love, together, form a strange frame for the young lovers, for not one of the loves is free from violence--be it beginning, middle, or end.

Although Midsummer is clearly a comedy, the other loves leave the audience with a growing awareness of the unfairytale-like reality of love.

What are some direct quotes of how Cleofilas was abused?

There are a number of quotes that describe Cleofilas' abuse, which was both physical and mental. 

Soon after her marriage, "the moment came, and he slapped her once, and then again, and again; until the lip split and bled an orchid of blood". 

Then later, symbolically profaning all her dreams, "He had thrown a book.  Hers.  From across the room.  A hot welt across the cheek.  She could forgive that.  But what stung more was the fact that it was her book, a love story...what she loved most now".

Cleofilas' husband cheated on her while she was delivering his first child - "A doubt.  Slender as a hair...No.  Her imagination...Coming home...something comforting...Her pillow.  Their bed...Sweet sweet homecoming.  Sweet as the scent of face powder in the air, jasmine, sticky liquor...smudged fingerprint...Crushed cigarette in a glass".

Cleofilas has to beg her husband to let her go to the doctor when she is pregnant again.  She promises "not to mention it", she will "say she fell down the front steps, or slipped...".  But the doctor finds "this poor lady's got black and blue marks all over".

Compare the death of Myrtle to the death of Gatsby in The Great Gatsby.

In The Great Gatsby by F. Scott Fitzgerald, both Mrytle Wilson and Jay Gatsby are victims of Tom Buchanan, the true villain of the novel who represents the careless recklessness of the Jazz Age. While Tom humors her with gifts, personal items, and a dog, Myrtle is deluded into believing he cares for her.  But, when she mentions Daisy's name, he brutally slaps her.   Tragically, she dies, too, in a brutal manner, a sacrificial victim to his excesses, 

...kneeling in the street...her mouth wide open and ripped at the corners as though she had choked a little in giving up the tremendous vitality she has stored so long.

Rather than have his wife charged with this murder, Buchanan conspires with Daisy to let Gatsby take the responsibility.  As the Buchanans in the house plan their strategy, much like Myrtle who is romantically deluded, Jay convinces himself that Daisy loves him and needs his protection as he watches solicitously outside the kitchen window as the Buchanan's conspire. However, Mr. Wilson, who has also been deceived by Tom Buchanan's machinations, makes Gatsby the sacrificial victim to the excesses of Tom Buchanan and Daisy as he believes that Gatsby is responsible for Myrtle's death. And, Jay Gatsby, too, dies brutally, sacrificed to illusion, face down in his pool, arms outstretched as though thrown from a cross.

What is the significance of John's re-seasoning the soup?

At the beginning of this scene, the stage directions say
that John comes in, tastes the stew, then puts more salt in it.  I think that we see the
importance of this a bit later in the scene.  We see this when John compliments
Elizabeth on how well the stew is seasoned.  She blushes with
pleasure.

To me, what is going on here is that John is
making a real effort to try to patch up their marriage.  He feels guilty about his
affair and he wants to make Elizabeth happy whenever he can.  So, here, he makes sure
that the stew will taste the way he likes it so he can compliment
her.

Identify the kinds of knowledge Hamlet values; discuss the ways in which he acquires makes use of that knowledge.

I'll have a go at your question.  Hamlet, without a doubt,
is intelligent, perceptive, and insightful.  This fact is evident throughout the play.
 As such, he seems to value and use different kinds of
knowledge.

First of all, he is an empiricist.  He is the
"observe'd of all observers."  Through his careful observation of others, he is able
deduce Claudius' excessive drinking, his mother's too sudden fall for Claudius,
Ophelia's betrayal, Polonius' and other of king's spies' espionage, and Claudius' guilt
(as he reacts to the Players). He makes use of these observations as he navigates
throughout the corrupted currents of the court, deftly managing Claudius' attempts to
contain him.

Hamlet also possesses cultural knowledge:  he
knows the Bible well (Notice his allusions in his conversation with Polonius in Act 2);
he knows Greek and Roman mythology; he is well versed in drama; he is astute in history
and current events.  Hamlet uses this knowledge to set a trap for Claudius, to elude
Polonius, and to connect with Horatio.

He is also rational
and logical.  Look at his most famous speech, "To be or not to be."  It is a well
reasoned argument, posing and answering the question of why we "bear the whips and
scorns of time" when we could our "quietus make with a bare bodkin."  The speech is a
beautiful piece of rhetoric, which outlines the pains of living, the temptation of
suicide, and the fear that causes us to cling to that which we know rather than to
travel to that "undiscovered country, from which no traveller returns."  Other examples
of his logical mind can be seen when he shows Claudius in Act 4, Scene 3 how a "king can
progress through the guts of a beggar," and in Act 4, Scene 4, when he analyzes the
nature of thought, man, and action and the relationship of all three.  More examples of
this type of analytical thinking occur in Act 5 in the graveyard scene and much earlier
in Act 2 with Rosencrantz and Guildenstern, with Hamlet's speech "What a piece of work
is man."  Perhaps it is this knowledge that Hamlet most values.  And perhaps it is this
type of thinking that leads to certain philosophical conclusions about action, man,
death, life that leads us to judge Hamlet as a prince of thought rather than a prince of
action.

Most of all, perhaps, Hamlet is intuitive.  He lets
his conscience guide him, which at times causes his most pronounced conflicts.  He is
torn between his love and loyalty to his father and his obvious reluctance to murder.
 He attempts to operate with conflicting values, attempts that have tragic
consequences.

How is the mockingbird theme used to unite the two plot elements of the Radley mystery and the Robinson trial?

Both Tom Robinson and Boo Radley serve as symbols of mockingbirds.  However, another interesting way to look at this is from Boo's point of view.  In the final chapter, Scout walks Boo home and pauses by his window.  She envisions what the world must have looked like from his vantage point.  She recounts watching the kids play and grow.  Then when they needed him (when they are attacked by Bob Ewell), Boo protects them. 

If you think about it, Jem could serve as a mockingbird symbol too.  He has done nothing but strive to help Boo (trying to get him to come out and realize they mean him no harm and only want to befriend him) and feel compassion for him (notice how hard he takes it when the knot in the tree is filled with cement and Boo is cut off from communicating with them or how he cries when he realizes Boo has mended his pants when he was trying to sneak Boo a note).  So from Boo's point of view, it would be a terrible sin to harm Jem since he has done nothing but provide - albeit mostly vicariously - entertainment and friendship.

When Boo rushes to defend the children - and kills Mr. Ewell - he is bringing an end to the repercussions of the Robinson trial.  Remember, Mr. Ewell was seeking revenge for how Atticus humiliated him on the stand.  Boo also brings a close to the mystery surrounding him in the novel too.