在氯化铝溶液中逐滴加入过量的氢氧化钠溶液,观察到的实验现象是() A.只放出气体

题型:选择题

问题:

在氯化铝溶液中逐滴加入过量的氢氧化钠溶液,观察到的实验现象是(   )

A.只放出气体

B.先有白色沉淀产生,最后沉淀全部溶解

C.只产生白色沉淀

D.既产生白色沉淀,又放出无色气体

考点:元素的性质生活中的元素(常量元素、微量元素)
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某化合物由碳、氢、氧三种元素组成,其红外光谱图显示有C-H键、H-O键、C-O键的振动吸收,该有机物的相对分子质量是60,则该有机物的结构简式可能是[ ]

A.CH3CH2CH2OH

B.

C.CH3CH2OCH3

D.CH3CH2CHO

题型:选择题

中学大队辅导员应有()年以上的教育教学工作实践。

A.3

B.1

C.2

题型:选择题

At exactly eleven Sir Percival knocked and entered, with anxiety and worry in every line of his face. This meeting would decide his future life,and he obviously knew it.

"You may wonder, Sir Percival,”said Laura calmly, “if I am going to ask to be released (免除)from my promise to many you. I am not going to ask this. I respect my father's wishes too much.”

His face relaxed a little, but one of his feet kept beating the carpet.

"No, if we are going to withdraw. (退出)from our planned marriage, it will be because of your wish, not mine.

“Mine?” he said in great surprise. “What reason could I have for withdrawing?

"A reason that is very hard to tell you," she answered. "There is a change in me.”

His face went so pale that even his lips lost their color. He turned his head to one side.

"What change?" he asked, trying to appear calm.

“When the promise was made two years ago,” she said, 44 my love did not belong to anyone. Will you forgive me, Sir Percival, if I tell you that it now belongs to another person?”

“I wish you to understand, “Laura continued, “that I will never see this person again, and that if you leave me, you only allow mc to remain a single woman for the rest of my life. All I ask is that you forgive mc and keep my secret."

‘I will do both those things, “he said. Then he looked at Laura, as if he was waiting to hear more.

"I think I have said enough to give you reason to withdraw from our marriage, “she added quietly.

“No. You have said enough to make it the dearest wish of my life to marry you, ” he said.

小题1:How did Percival feel during his meeting with Laura?

A.Angry.

B.Calm.

C.Nervous.

D.Excited.小题2:We can learn from the passage that        .

A.Laura had once promised to marry Percival

B.Laura's father wished to end her marriage

C.Percival had been married to Laura for two years

D.Percival asked to be released from the marriage小题3:The passage is probably taken out of              .

A.a novel

B.a report

C.a diary

D.an essay

题型:选择题

反复多次脱位者称为

A.先天性脱位

B.陈旧性脱位

C.复杂性脱位

D.完全性脱位

E.习惯性脱位

题型:选择题

无论是低等生物,还是高等动植物和人,都会由于基因突变而引起生物性状的改变。说明了基因突变的哪个特点()

A.随机性

B.不定向性

C.普遍性

D.低频性

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