单词填空

1. Are there many ______( 印度人) in your city?

2. My teacher told me that to be successful requires _____(某种) efforts.

3. Which ______(时期) of history would you most like to live in?

4. ______(不管多么) difficult it was he'd try to help us.

5. Do you know the ______(发言者) at the meeting?

6. I can't ______(表达) my opinion in English because I am not good at it.

蓄电池在0℃以下的条件使用时，将电解液密度适当（），以防止电解液结冰，将蓄电池外壳冻裂。

A.恒定

B.调整

C.降低

D.提高