一般来讲，高氟区的界定是饮水中氟的含量超过（） A.0.5mg/L B.1.0m

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问题单项选择题 A1/A2型题

一般来讲，高氟区的界定是饮水中氟的含量超过（）

A.0.5mg/L

B.1.0mg/L

C.1.5mg/L

D.2.0mg/L

E.2.5mg/L

答案

参考答案：B

选择题

What vegetable ____________ the letter " a " ?[ ]

A. has

B. have

C. are

选择题

“Have you seen the film?” he asked me. →He asked me _______.

A．had I seen the film

B．have I seen the film

C．if I have seen the film

D．whether I had seen the film