用所给单词的适当形式填空。

1. We need to produce a lot of             _ (medical) to save those people who get HINI flu.

2. More and more parents are _          _ (worry) about their children playing computer games.

3. As a student, you should learn more            _ (know) from your teachers.

4. All the land was            _ (cover) by the white snow when we got up last Sunday.

5. I think playing computer games is not _            (help) to your study.