Can you check these sentences for me?

1) They search to not throw away so manu plastic bags (they try not to throw so many .... away??)
2)He enjoyed not having a conscience (he enjoyed having no conscience)
3)he couldn't keep in control that situation because he transformed so fast and he preferred to (he couldn't keep his transformation under control and he decided to ..)
4) At a bus stop a man asked her to stand up (Is at correct??)
5) He had a dream that one day his children (is it correct?)
6) He was really panicked because.. (he was really frightened)
7) I can't understand this sentence at all Can you help me correct it; The accumulate of bags in the sea stop the beat from the sun of the coral reef???
8)She was returning home by bus (on a bus??)
9) Blacks made give up their seats to whites (blacks were made to give up ..)
10) He wanted a world where anybody judged someone for his skin's color (he wished a world where no-one would be judged by the color ...)
11) the winscreen crashed. (the windscreen smashed)
12) Paul uses the Internet for sending his homework questions to a homowork agency that sends him the answer. Doing so he passed a course (How would you correct the last one?
Thanks

1. They try not to throw away so many plastic bags.

2. He enjoyed having no conscience.

3. He couldn't keep his transformation under control, so he decided to .

4. (correct)

5. So far it's fine, but it's incomplete.

6. "frightened" is better

7. The accumulation of plastic bags in the ocean stops the heat of the sun from reaching the coral reef as it should.

8. Either expression is fine.

9. Blacks were made...

10. He wanted a world in which no one would be judged by the color...

11. The windscreen was smashed. (The word "windscreen" is English; the word "windshield" is American!)

12. First sentence is fine. Second sentence: "By doing so, he passed the course."