The employee had to break off() the conversation in order to wait on his manger.
A. continue
B. hurry
C. begin
D. discontinue
(),we often hear only what we want to hear, rather than really listening to other people.
A. Traditionally
B. Additionally
Conditionally
D. Exceptionll
()是指在工业上能从其中提起一种或数种有用金属元素的矿物。
A. 金属矿物
B. 矿石矿物
C. 有用矿物
D. 天然矿物
不同用途的水,均应满足一定的水质要求,也就是()。
A. 水质指标
B. 水质好坏
C. 水质标准
D. 水质特征