（）防止超越行程的保护装置是缓冲器。
参考答案：错
These wild flowers are so special that I would do ________ I can do to save them.[ ]
A. whatever
B. that
C. which
D. whichever
手工钨极氩弧焊机焊炬的控制电路电压在交流时不应超过（）。
A.36V
B.40V
C.48V
D.50V
