用所给词的适当形式填空。

1. Bill Gates became ________ (interest) in software when he was only 13.

2. Bill Gates is the man who is taking the ________ (person) computer into everyone's home.

3. Mrs. Wang is very nice. She is ________ (friend) to us every student.

4. Grace is very sure of ________ (she).

5. My father plans ________ (retire) at the age of 50.

随着水含量的升高，甲铵的熔点（）。