凸轮轴的功用是利用凸轮使各缸进、排气门关闭。()
参考答案:错
"She's not a dancing teacher, is she?" "________."
A.Yes, and she isn'
B.Yes, but she was
C.No, but she isn't
D.No, but she was
在原始人懂得戴面具,懂得化妆的时候,()的萌芽就产生了。
A、戏剧
B、电影
C、音乐
D、文学