水联运的目的是什么？
参考答案：
考察机泵的使用性能；检查各种仪表的使用性能。
These kids are quick at learning. We had better have them __ in a new way.
A．having been trained
B．training
C．being trained
D．trained
铵油炸药由（）和燃料油组成。
A.碳酸钙
B.工业用盐
C.硝酸铵
D.石灰
