1.what if it Will rain tomorrow?

正确的应该是
1 What if it rains tomorrow 这里 what if 表假设,这里后面写一般现在时就OK了
2 I don't know how to do it 少了个it语义就不完整了
3 You can look up the word in the dictionary 因为(look up 是查阅的意思)
4 What will you do to help these poor children 这里do 后面要加to不定式表目的,不然就两谓语了
5 I like music that has great lyrics.这里 music显然后面要接单三,所以将have改has
6 Reading in the Sun is bad for your eyes.在太阳底下读书对眼睛不好.这是个很常见的说法 改under为in
7 Before the movie,we went for Japanese food yesterday evening 因为句末yesterday evening所以过去式(其实应该是过去完成时,但是考虑到我不知道你们学到过去完成式没有)
8Mom bought me a skirt and it suited me fine 这里bought是谓语 后面接的是宾语,所以把my改me.