Although the causes of cancer _____, we do not yet have any practical way to prevent it.
A.are being uncovered |
B.have been uncovering |
C.are uncovering |
D.have uncovered |
Then professor walked onto the platform and seated himself in a chair, ______ for answering questions.
A.had prepared | B.being prepared | C.preparing | D.prepared |
— Did you know any French before you arrived in Washington?
— Never ______ it, actually.
A.had I learned | B.have I learned | C.I learned | D.was I learning |
She was such a proud person that she would die ______ she would admit she was wrong.
A.rather than | B.until | C.after | D.before |
— Did your sister pass the exam?
— She failed and is in low spirits.
— I'm sorry for her.
— ______.
A.Thank you | B.You're welcome | C.I would think so | D.Never mind |
He is only too ready to help others, seldom, ______, refusing them when they turn to him.
A.if never | B.if ever | C.if not | D.if any |