对深度超过( )m,可能存在危险性气体的挖掘现场,应进行气体检测。
A.1.2
B.1.5
C.1.8
参考答案:A
用所给单词的适当形式填空
1. Can you give me your _________(explain) for your absence?
2. During the Spring holidays there are many _______ (culture)activities.
3. In America, we often greet people by ________(shake) hands or hugging.
4. I'll call you as soon as I ________(get to) New York.
5. Could you tell me some special customs that ________(not find) in Chinese culture?
有红、黄、蓝三种颜色的小珠子各4颗混放在口袋里,为了保证一次能取到2颗颜色相同的珠子,一次至少要取______颗.
如果要保证一次取到两种不同颜色的珠子各2颗,那么一定至少要取出______
颗.