study is difficult

I solve the physical chamisry question about 3hours.
BUT!!!!!!! I don't understand !!!! Many questions are make me a fool.
I'm very dissapointed about my brain .
 This question is homework and  similar question appear in examination to next week. So very important to solving question.
I want to give up...............

weather

Weather is too difficult for me



Time is fall but I felt many weathers in one day.  morning is cool, daytime is hot, night is very cold.
these days, daily temperature range is too big, so I don't know what I wear clothes. Now is in between seasons so I got a cold  !! I'm very tired because of this.

 I want to go autumn colors trip but wind is really strong , many leaves are fail down. And my body condition is really bad either.  Thease day weather is really difficult for me...