The （）were carefully inspected before we i_爱下问搜题

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问题单项选择题

The （）were carefully inspected before we issue the Phytosanitary Certificate.

A．animal products

B．plant products

C．machines

D．electronic toys

答案

参考答案：B

单项选择题

图示结构（E为常数），杆端弯矩（顺时针为正）正确的一组为（）。

A．M_AB=M_AD=M/4，M_AC=M/2

B．M_AB=M_AC=M_AD=M/3

C．M_AB=M_AD=0.4M，M_AC=0.2M

D．M_AB=M_AD=M/3，M_AC=2M/3

多项选择题

双窗口光缆光纤特性的测试有：（）mm。

A.1310

B.1300

C.1550

D.1510