We had already sent out the invitation cards, but we didn't know how many people（）

A.come

B.are coming

C.came

D.have come

When William hurried home, he found that his mother ____already ____to hospital.

A、has; been sent

B、had; sent

C、has; sent

D、had; been sent

I can't accept your invitation ______I've already had an appointment with my friend.

A．which

B．that

C．in which

D．in that

()separate cover, we have already sent you samples () various sizes of shoes.

A、Below,of

B、Under,of

C、By,of

D、By,including

When he came to the laboratory the next morning, the author______.

A．saw that his cards had already been rearranged

B．realized that the wasp had been trying to help

C．found evidence of the wasp's intelligence

D．found his index cards still scattered about the room

B．To help her students

C．To conduct a research

D．To improve public health