Although the causes of cancer ____we do not yet have any practical way to prevent it.
A．a(chǎn)re being uncoveredB．have been uncovering
C．a(chǎn)re uncoveringD．have uncovered
A
考查被動語態(tài)。選項A是現(xiàn)在進行時的被動；選項B是現(xiàn)在完成進行時的主動語態(tài)；選項C是現(xiàn)在進行時的主動語態(tài)；選項D是現(xiàn)在完成時的主動語態(tài)。根據(jù)題意：雖然癌癥的成因長在被揭示，但我們眼下還沒有防止它的實用方法。故答案為A.
練習(xí)冊系列答案
相關(guān)習(xí)題

科目：高中英語 來源：不詳 題型：單選題

Don’t worry. I’ll         in my home for a week.
A．stay you upB．put you upC．put up youD．put you away

查看答案和解析>>

科目：高中英語 來源：不詳 題型：單選題

—Joan，what ________ in your hand?
—Look！It's a birthday gift for my grandma.
A．had you heldB．a(chǎn)re you holding
C．do you holdD．will you hold

查看答案和解析>>

科目：高中英語 來源：不詳 題型：單選題

With more forests being destroyed, huge quantities of good earth ______ each year.
A．is washing awayB．is being washed away
C．a(chǎn)re washing awayD．a(chǎn)re being washed away

查看答案和解析>>

科目：高中英語 來源：不詳 題型：單選題

— ________ for the glass! —It’s OK. I’m wearing shoes.
A．Look outB．Walk out
C．Go outD．get out

查看答案和解析>>

科目：高中英語 來源：不詳 題型：單選題


一Ready to give up guessing，Sandy?
一No，no，hold on! I think I______ at the answer now．
A．a(chǎn)rriveB．a(chǎn)m arrivingC．have arrivedD．will arrive

查看答案和解析>>

科目：高中英語 來源：不詳 題型：單選題

—What happened? I called you several times yesterday evening, but I couldn't get through.
—Sorry, my sister and I ________ on the phone all the time.
A．talkedB．have talked
C．were talkingD．have been talking

查看答案和解析>>

科目：高中英語 來源：不詳 題型：單選題

—Guess what，we've got our visas for a short－term visit to the UK this summer.
—How nice！You ________ a different culture then.
A．will be experiencingB．have experienced
C．have been experiencingD．will have experienced

查看答案和解析>>

科目：高中英語 來源：不詳 題型：單選題

In the last few years thousands of films ____ all over the world.
A．have producedB．have been produced
C．a(chǎn)re producingD．a(chǎn)re being produced

查看答案和解析>>

同步練習(xí)冊答案