Thank you very much for your help. Here are the last sentences of the day.

1)The opposition between dark and white works in reverse.
2)The poet teaches men how to understand themselves better. The subject (matter?) of poetry is often a normal (common) man with his problems.
3)Black (the black, darkness) acquires negative connotations whereas white becomes negative. This happens because Marlow is against colonialism.
4) The Romantics exalted the individual, the rebel because these people took a position (rebelled) against society which was viewed as an evil (force).
5) One of the most important characteristics (features, peculiarities) of the child was its (his?) uncorrupted sensibility which brought him nearer to God.
6)) For the frame narrator light (the light?) was associated with calm, beauty and peace while the dark (darkness) with the evils caused by European colonization.

1)The opposition between dark and white works in reverse.

I'm not clear on what you mean by "opposition." Do you mean contrast? Or maybe "juxtaposition"? http://thesaurus.com/browse/opposition

2)The poet teaches men how to understand themselves better. The subject of a poem is often a normal man with his problems.

3) The use of black acquires negative connotations, whereas white becomes negative.<~~??? This happens because Marlow is against colonialism.

4) The Romantics exalted the individual, the rebel because these people<~~Who are "these people" - the Romantics? or the rebels? rebelled against society, which was viewed as an evil force.

5) One of the most important characteristics of a child was his uncorrupted sensibility, which brought him nearer to God.

6)) For the frame narrator, the light was associated with calm, beauty, and peace, while darkness was associated with the evils caused by European colonization.

Please note the addition and correction of all commas. All are needed; you have several parenthetical clauses in there, and they need to have commas setting them apart from the rest of the sentence.
http://grammar.ccc.commnet.edu/grammar/commas.htm Read #4 very carefully.

1) The opposition between dark and white works in reverse.

The phrase "opposition between dark and white" refers to the contrast or contradiction between darkness and whiteness. In this context, "works in reverse" means that the usual associations or meanings attributed to dark and white are flipped or reversed. To understand this sentence in more detail, you can consider the usual associations of dark and white and then think about how they might be reversed in the given context.

2) The poet teaches men how to understand themselves better. The subject (matter?) of poetry is often a normal (common) man with his problems.

This sentence talks about the role of a poet and the subject matter of poetry. It suggests that poetry can help individuals gain a better understanding of themselves. The subject of poetry is often a common man, someone ordinary with their own set of problems. To delve deeper into this sentence, you can think about how poetry can provide insights into human experiences and emotions, and how it can relate to the struggles and challenges faced by ordinary people.

3) Black (the black, darkness) acquires negative connotations whereas white becomes negative. This happens because Marlow is against colonialism.

This sentence highlights a shift in connotations associated with the colors black and white. It states that black, which traditionally carries negative connotations, becomes a positive attribute, while white, which traditionally carries positive connotations, becomes negative. This shift occurs because the character Marlow is portrayed as being against colonialism. To understand this further, you can analyze how the author uses symbolism and imagery to convey contrasting meanings and perspectives.

4) The Romantics exalted the individual, the rebel because these people took a position (rebelled) against society which was viewed as an evil (force).

This sentence discusses the Romantic period and their admiration for individuals who rebelled against societal norms. The Romantics held the individual in high regard because they saw those who took a position against society as rebelling against what they perceived as an oppressive or negative force. To better understand this statement, you can explore the historical, social, and literary context of the Romantic period and the themes they championed.

5) One of the most important characteristics (features, peculiarities) of the child was its (his?) uncorrupted sensibility which brought him nearer to God.

This sentence talks about the significance of a child's uncorrupted sensibility, which draws the child closer to God. The author suggests that this quality is one of the most important attributes of a child. To delve deeper, you can consider the concepts of innocence, purity, and spirituality associated with children and how they relate to the idea of being closer to God.

6) For the frame narrator light (the light?) was associated with calm, beauty, and peace while the dark (darkness) with the evils caused by European colonization.

This sentence describes the associations made by the frame narrator between light and dark. Light is linked to attributes such as calmness, beauty, and peace, while darkness is associated with the negative effects arising from European colonization. To gain a deeper understanding, you can explore the symbolism of light and dark and how they are used to convey themes of oppression, imperialism, or the struggle between good and evil.