“藕”是莲的（）。
A、茎
B、根
参考答案：A
—_____ did you stay in your hometown?
—For two weeks. [ ]
A. How often
B. How long
C. How many
D. How many times
更换附有吸上线(或回流线)两相邻扼流变压器的中性连接板时，应怎样进行？
