液体己内酰胺贮槽在首次收料之前必须()。A、除去所有金属微粒 B、彻底清洗 C、彻底

题型:多项选择题

问题:

液体己内酰胺贮槽在首次收料之前必须()。

A、除去所有金属微粒

B、彻底清洗

C、彻底干燥

D、氮气置换

考点:己内酰胺装置操作工己内酰胺装置操作工(中级)己内酰胺装置操作工(中级)题库
题型:多项选择题

已知a,b是实数,则“|a+b|=|a|+|b|”是“ab>0”的(  )

A.充分不必要条件

B.必要不充分条件

C.充分必要条件

D.既不充分也不必要条件

题型:多项选择题

若(1+tgθ)8展开式的第4项为7,则sin2θ的值为______.

题型:多项选择题

关于低温保存细菌正确的是()

A.低温保存细菌时,温度必须迅速降低,否则细菌会死亡

B.冷冻时加入甘油、血清、牛奶等保护剂可使细菌存活量增加

C.反复冻融可使大部分细菌死亡

D.目前保存菌种最好的方法是冷冻真空干燥法

E.低温状态下真空抽干去尽水分,可避免解冻时损伤细菌

题型:多项选择题

肾病综合征的治疗是

A.血液透析
B.泼尼松加环磷酰胺
C.保养、对症治疗
D.甲泼尼龙冲击

题型:多项选择题

I realized that I was getting cold, and felt it was probably time to go back to the apartment, so I put my collar up against the wind and began to walk back up the cold street. I managed to get some food from a vendor(小贩), and walked on.

About twenty-five minutes later I knew that something was wrong. It was getting very, very cold, there were no streetlights, and the hill I was hoping to see on my right was nowhere in sight.  There was almost no light except for mysterious red crosses shining from the tops of churches, and I was beginning to get worried.  To cut a long story short, I had walked the wrong way from a crossroads, and had wandered miles in the wrong direction. My head was aching from the cold, and I couldn’t think straight. Turing around, I started back, and a long time later was outside the house I had set off from. It was at about that time I realized that I had a gate key but no house key.  How happy I was when I found that the front door was open—my only piece of good luck that day.  My apartment was of course locked, my head felt like it was about to explode, and my hands and feet were freezing.

I tried turning the handle.  No luck.  I tried another key from England.  I wanted to avoid waking the family downstairs, so despite the fear of an early death from cold, I couldn’t break the door down.  What would my hosts think? I pulled an ATM card from my pocket and forced it alongside the inside of the lock. I didn’t think it would work, but after fifteen minutes of trying, I heard a click.  Another couple of minutes later the door was open.  Relieved, I took off my clothes in the dark and got into bed.

小题1:The purpose of the passage is mainly to            .

A.tell us how difficult it is living abroad

B.show us how terrible the weather was

C.tell us an unusual experience abroad

D.show us how afraid the author was小题2: What made the author find he had walked the wrong way?

A.He didn’t see the house.

B.A vendor reminded him.

C.The street name reminded him.

D.He didn’t see the hill.小题3:What can we learn from the passage?

A.The front door was closed.

B.The house had many locks.

C.The author woke the hosts.

D.The author came from England.小题4:From the passage we can infer that the author was            .

A.careful

B.careless

C.excited

D.annoying

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