用所给单词的适当形式完成句子.

1. My father spent two hours        _ (cover) the vegetables last night.

2. To our surprise, the little boy can write all the words        _ (correct).

3. I think this dictionary is very        _ (help) to you if you want to learn English.

4. Look! Your house _         (burn).  Let's go and put it out quickly.

5. I feel very        _ (pain) all over my head.  What's wrong with me?