用单词的适当形式填空

1. I must       (finish) my homework first.  

2. She       (have)       (get) up early yesterday.  

3. He       (not have to) finish the work today.  

4. My mother doesn't let me       (read) in bed.  

5.        (not talk). It's time for class.

改变硅酸盐水泥的矿物组成可制具有不同特性的水泥，提高（）、（）矿物的含量可制得快硬水泥。