根据句意、首字母提示完成单词。

1. Sam's favorite subject is ________ (物理学).

2. Please ________ (翻译) these Chinese sentences into English.

3. I want to i ________ my English, so I make friends with an American girl.

4. I can't go to the movies this Saturday. I have to have my piano l_______.

5. There are many t ________ visiting Beijing every year.

设t=0时，投入工作的日光灯有1000只，以天作为度量时间的单位，当t=365天时，发现有25只日光灯坏了，一年时的工作可靠度为（）。

A．9.75%

B．0.25

C．0.97

D．0.975