— Nancy was badly injured in the accident yesterday and she was sent to hospital. — Oh, really? I（）. I（） visit her.

A.didn’t know；will go to

B.don’t know；will go to

C.didn’t know；am going to

D.haven’t known；am goingt o

离心泵的连续输水是靠泵轴带动叶轮和水高速旋转而形成的（）作用来完成工作的。

A、压力

B、离心力

C、向心力

D、动力