罗茨风机振动过大的原因是（）。A.转子与转子间间隙过大 B.传动齿轮键松动 C.转子

 As I ______, I suddenly remembered that it was your birthday.

A．to feed my cats

B．am feeding my cats

C．had feed my cats

D．was feeding my cats

The classroom is crowded with children_____ have poor eyesight, all of ____ interested in painting.

A．who; whom

B．that; whom

C．who; them

D．that; who

合同是双方的民事法律行为，合同的订立必须由当事人双方参加。

短信对账方式适用于日均余额（）元以下的账户。

A.1万

B.2万

C.3万

D.5万

引导手信号，准许列车进入车场或车站，昼间（）信号旗高举头上左右摇动。

A.拢起的黄色

B.拢起的红色

C.展开的黄色

D.展开的红色