进气管回火时PCV阀()。
A.全开
B.半开
C.关闭
D.开或关由当时发动机转速决定
参考答案:C
下列违背价值规律的是[ ]
A.钻石的稀缺程度比水高,因而钻石比水贵
B.古代少数民族用毛皮与汉族交换等价值的大米
C.甲用一块砖头充当秦代文物,换走乙一块黄金
D.制造火箭的成本比汽车高,因而火箭比汽车贵
China stands ready to join hands with all other countries to _________ the serious problems resulting from the energy crisis and build an even better future for the generations to come.
A.tend to
B.cut off
C.hold back
D.deal with