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问题 选择题

有下列几种有机物.

 （1）CH3COOCH3                            （2）CH2=CHCH2Cl

（3）CH2="CH—CHO"                其中既能发生水解反应，又能发生加聚反应的是

A．(1)与(4)

B．(2)与(3)

C．(2)与(4)

D．(1)、(3)和(4)

答案

 C

选择题

Luckily, we’d brought a road map, _________ we would have lost our way.

A．without it

B．with that

C．without which

D．without that
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单项选择题

For many years, the principle goal of computer (73) was to write short pieces of code that would execute quickly. The (74) needed to be small, because memory was expensive, and it needed to be fast, because processing power was also expensive.

A．users

B．programmers

C．computer

D．program
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