有一固体混合物，可能由Na2CO3、Na2SO4、CuSO4、NaClCaCl2

---Do the people in Australia speak French?

--- ____________.

A．Yes, they are.

B．No, they aren’t.

C．Yes, they do.

D．No, they don’t.

When one makes new friends, don't forget _____ old ones. [ ]

A. to put up with

B. losing sight of

C. to keep track of

D. keeping in touch with

刘备死时几岁？

我国推进现代化进程要实现城乡二元经济结构向一元的（）

A．现代经济转变

B．封闭型经济转变

C．传统经济转变

D．数量扩张型经济转变

移动变电站主接地极和辅助接地极距离不得小于（）m，接地电阻不大于2Ω。

A.9

B.7

C.5

D.3