Only by increasing the number of doctors by 50 percent ________ properly in this hospital．

A．can be the patients

B．can the patients be treated

C．the patients can be treated

D．treated can be the patients

A serious study of physics is impossible ________ some knowledge of mathematics．

A．against

B．before

C．beyond

D．without

It was only after he had read the papers ________ Mr．Gross realized the task before him was extremely difficult to complete．

A．when

B．that

C．which

D．what

It may not be a great suggestion．But before ________ is put forward, we'll make do with it．

A．a good one

B．a better one

C．the best one

D．a best one

The watch was very good, and he ________20 percent down for it．

A．paid

B．cost

C．bought

D．spent

We ________ very early so we packed the night before．

A．leave

B．had left

C．were leaving

D．have left

Since nobody gave him any help, he ________ have done the research on his own．

A．can

B．must

C．would

D．need

I got to the office earlier that day, ________ the 7：30 train from Paddington．

A．caught

B．to have caught

C．to catch

D．having caught

When I arrived, Bryan took me to see the house ________ I would be staying．

A．what

B．when

C．where

D．which

I was glad to meet Jenny again,________ I didn't want to spend all day with her．

A．but

B．and

C．so

D．or