单词拼写。

1. We shouldn't have a wrong ____(态度)towards the students who are poor at their studies.

2.He is _____  (有决心的)to catch up with the others.

3. He was too____  (顽固的)to admit that he was wrong.

4. The new bridge has been finished two years ahead of_____(日程).

5.We are looking for someone who is___  (可靠的)and hard-working.

使用铂皿时，应避免与（）接触。

A.水

B.王水

C.双氧水