____some doubt among scientists about the cause of cancer.
A．It existsB．There exists C．There is existingD．It is existing
B
考查特殊句式。There be結(jié)構(gòu)中的系動(dòng)詞換成其它的系動(dòng)詞如exist, happen，seem等；系動(dòng)詞是沒(méi)有進(jìn)行時(shí)的。所以排除CD。句意：在科學(xué)家中對(duì)于癌癥的原因存在著一些懷疑和爭(zhēng)論。
練習(xí)冊(cè)系列答案
相關(guān)習(xí)題

科目：高中英語(yǔ) 來(lái)源：不詳 題型：單選題

It was the third time that the boy _________ late. So his teacher got very angry.
A．have beenB．was
C．had beenD．was being

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：單選題

I would rather ________the football match last night with my friends. Otherwise，I would have finished my paperwork by now.
A．not have watched B．not watch
C．hadn't watchedD．haven't watched

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：單選題

The E-mail Jack had looked forward to ______ last night at last and he was very happy.
A．a(chǎn)rrivedB．a(chǎn)rrivingC．had arrivedD．a(chǎn)rrived

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：單選題

He is so addicted to smoking that ________ seems to be no chance of talking him into quitting.
A．thisB．whatC．itD．there

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：單選題

The bank is reported in the local newspaper ______ in broad daylight yesterday
A．to be robbedB．to have been robbedC．robbedD．having been robbed

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：單選題

You are always telling me I am lazy. Look at your room. What a mess it is! ________.
A．The day has eyes, the night has ears
B．The great thieves punish the little ones
C．That is like the pot calling the kettle black
D．When one will not, two cannot quarrel

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：單選題

I couldn’t believe it, but ______ in black and white, signed by the bank manager.
A．it there wasB．there was itC．was it thereD．there it was

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：單選題

To show our respect, we usually take our gloves off _______ we are to shake hands with.
A．whoeverB．wheneverC．whicheverD．wherever

查看答案和解析>>

同步練習(xí)冊(cè)答案