在低压电路的组成部件中，（）串联在低压电路中。
A.配电器
B.火花塞
C.附加电阻
D.分火头
参考答案：C
There are __ in the reading room, but many of those books aren’t __ to read． [ ]
A. enough books，enough easy
B. enough books，easy enough
C. book enough，easy enough
D. book enough，enough easy
缺铁性贫血者，铁的吸收率（）
A.10%
B.15%
C.20%
D.25%
E.30％
