用所词的适当形式填空。

1. A large number of _______ (foreign) visit Guizhou province these years.

2. Thank goodness! The letter I was looking forward to _______ (reach) me at last.

3. Hainan Island is a _______ (wonder) place to spend summer.

4. The dinner room must _______(clean) three times a day.

5. My cousin is used to _______ (study) with his new friends in Australia.

锅炉与压力容器使用的压力表一般都是（）式，而且大都是单弹簧管式压力表。

A.有液柱式

B.电接点式

C.弹性元件式

D.活塞式