____ to Anne's birthday party, Mr. Brown is now searching shop after shop for a nice present for her.

A．Having invited

B．Having been invited

C．Have been invited

D．Being invited

灰渣泵与其轴封水泵之间设有连锁，防止（）。

A.灰渣泵未启动时，轴封泵先启动；

B.轴封泵未启动时，灰渣泵先启动；

C.灰渣泵与轴封泵不同时启动；

D.前三种说法都不对。