合成塔为更换催化剂而卸出“失活”的催化剂,应先()。 A.将催化剂冷却后再卸出 B.

题型:单项选择题

问题:

合成塔为更换催化剂而卸出“失活”的催化剂,应先()。

A.将催化剂冷却后再卸出

B.通N2进行置换后再卸出

C.对反应塔的催化剂进行"钝化"操作后,才能卸出

D.无需任何处理,直接卸出

考点:化学工程精细化工工艺学精细化工工艺学题库
题型:单项选择题

How do you remember the way to your house? Where do dreams come from? It is your brain(大脑) that does these things. A British scientist showed that “sleep can improve one’s memory.” It’s not a dream for students to study when they sleep. In fact, your brains is working day and night. If you learn words before bed, a certain part of the brain may help you to remember the words while you sleep. What’s more, another scientist in the USA found that there was a “talent button(天才按钮)” in the human brain. It might make a person more talented.

There are more interesting things about the brain. Your brain uses less energy than a fridge light. Just two bananas can give the brain enough energy to work for a whole day. According to some scientists, yawning(打哈欠) keeps our brains “cool”, which makes us think quicker.

Here are some pieces of advice to keep a good brain:

Eat healthy food.

Get a lot of playtime or exercise.

Don’t drink or smoke.

Use your brain a lot.

小题1: A British scientist found out that ________ could improve our memories.

A.drink

B.dreams

C.sleep

D.bananas小题2: According to the passage, if we want to have a good brain, we should ________.

A.use our brains more

B.sleep fewer hours

C.work longer hours

D.remember fewer things小题3:Which of the following is TRUE according to the passage?

A.Our brains only work in the daytime.

B.Our brains need much energy every day.

C.Smoking can keep our brains healthy.

D.Getting exercise is good for our brains.

题型:单项选择题
仿照例子,写句子。
1. Who is this? 
    This is a boy.
2. Who __________ this? 
    This is a __________.
3. _______________________?
    _______________________.
4. _______________________?
    _______________________.
                                                                               
题型:单项选择题

简答汉防己与木防己功效异同。

题型:单项选择题
如图所示,理想变压器原副线圈匝数之比为4:1,原线圈接入一电压为u=220sin100πtV的交流电源,副线圈接一个R=27.5Ω的负载电阻.则下述结论正确的是(  )

A.副线圈中电压表的读数为55V

B.副线圈中输出交流电的周期为0.01s

C.原线圈中电流表的读数为0.5A

D.原线圈中的输入功率为110W

题型:单项选择题

排尿突然中断、排尿困难和疼痛()

A.输尿管结石

B.膀胱结石

C. * * 结石

D.肾结石

E.纯尿酸结石

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