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【单选题】
Listen carefully and decide which of the four suggested answers marked A, B, C and D is the closest in meaning. News summary 4.mp3:A.
Astronauts have detected the light from a star born 13 billion years ago.
B.
A Nature article claimed that the universe was born about 30 billion years ago.
C.
NASA scientists detected the light from the universe’s first stars.
D.
The stars were created along with the universe itself.
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举一反三
【简答题】古液碱 A ( C8H15ON )是一种生物碱,存在于植物中。它不溶于氢氧化钠溶液,但可溶于盐酸。它不与苯磺酰氯作用,但可与苯肼作用生成相应的苯腙。 A 与 NaOI 作用生成黄色沉淀和一个羧酸 B ( C7H13O2N )。 B 与 CrO3 强烈氧化,转变为古液酸 N- 甲基 - 吡咯烷甲酸( C6H11O2N )。写出 A 和 B 的名称。 A B
【简答题】金属A与过量的干燥氯气共热反应生成无色液B,B又可与金属A作用转化为固体C。将B溶于盐酸后通入H2S气体得黄色沉淀D,D可溶于Na2S 溶液得无色溶液E。将C溶于稀盐酸后加入适量HgCl2有白色沉淀F生成。向C的盐酸溶液中加入适量NaOH溶液有白色沉淀G生成。G溶于过量NaOH溶液得无色溶液H。向H中加入BiCl3溶液有黑色沉淀I生成。试确定A、B、C、D、E、F、G、H、I各代表何物?
【简答题】关于网店推广说法正确的有()
【单选题】This is a _____ map and it didn’t take me much time to come here from the station. [ ]
A.
help
B.
helpess
C.
helpful
D.
helping
【简答题】If they (be) ______ here, they would help you to solve the problems of the computer.
【简答题】碱A（C 8 H 15 ON）是一种生物碱，存在于植物中。不溶于NaOH水溶液而可溶于盐酸中。不与苯磺酰氯作用，但能与苯肼作用生成相应的苯腙。它与NaOI作用生成黄色沉淀和一个羧酸B（C 7 H 13 O 2 N）。用Cr 2 O 3 强烈氧化，B可转化为酸（C 6 H 11 O 2 N），即N-甲基-2-吡咯烷甲酸。试写出A，B的结构式。
【单选题】— Betty, will you please come here and help me? — Sorry, she is not here. She _____ to the cinema. May I help you? [ ]
A.
goes
B.
was going
C.
will go
D.
has gone
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