用might, may, probably, because, so或but完成句子。

1. It's warm in the day,______it______be cold in the evening.

2. Bring your swimsuit,______you ______  want to swim in the sea.

3. It______rain from time to time in spring, ______we'd better take a raincoat.

4. Buy a good map______you're______lost in a big city.

5. It______be a storm,______they have to stay at home tomorrow.

6. We______go to Xi'an for our holiday,______it's an interesting city.

7. You don't study hard, ______you______fail in this exam.

任何系统的管理手段、管理过程等必须构成一个连续封闭的回路，才能形成有效的管理活动，这就是安全管理基本原理的（）。

A.反馈原理

B.弹性原理

C.动力原理

D.封闭原理