用盐酸作原料制取二氧化碳时,制得的气体中,常混有的杂质是[ ] A.氮气和稀有气

题型:选择题

问题:

用盐酸作原料制取二氧化碳时,制得的气体中,常混有的杂质是       [ ]

A.氮气和稀有气体  

B.空气和氯化氢  

C.水蒸气和氯化氢  

D.空气和水蒸气

考点:二氧化碳的制取和收集
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《中华人民共和国消防法》规定,住宅区的物业服务企业应当对管理区域内的消防设施进行维护管理,提供消防安全()。

A.管理服务

B.监督检查服务

C.防范服务

D.防控服务

题型:选择题

If you have no special plans for your holidays, why not spend your time helping others?Don’t believe those people who say that young people today often think only of themselves. It’s not true at all. More and more young people in the USA volunteer to spend their school holidays working for others. And they don’t do it for money. Here are some of their stories.

Alice, 17

I’m going to help the Forest Center build new hiking paths in the mountains. It’s going to be great fun — I’ll spend the whole summer living in a forest and breathing the clean mountain air. I’m going to sleep under the moon and stars. It will be a nice sport, and I’ll be able to do something good at the same time!

Jason , 18

This summer, I’m going to volunteer with Special House Program. They build good, less expensive houses and sell them to families that are not very rich. They’ll teach me what to do, so I’ll help people and also have a chance to learn how to build houses.

Trish , 16

I’m going to teach children who have trouble in reading. I’ll work for a program called Reading for Life. Every day, I’m going to help them choose and read books that they like. I want to be a teacher, and I love children and reading, so this is going to be a great experience for me.

小题1:What does Alice plan to work for others in summer?

A.To sleep under the moon and stars.

B.To breathe the clean mountain air.

C.To help build hiking paths in the mountains.

D.To spend the whole summer living in a forest.小题2:The writer’s idea in this passage is ______.

A.school students should do some hiking in summer.

B.it’s good to do something good for others in vacation.

C.helping children to choose and read books is a good way.

D.breathing clean mountain air is good for health.小题3:Which is the most possible title (标题) for this passage?

A.Reading for Life

B.A Special House Program

C.The Forest Centre

D.Young American Volunteers

题型:选择题

关于纵裂的描述,不正确的是()。

A.纵裂内是由硬脑膜构成的大脑镰

B.内含静脉窦

C.内含大脑前、中动脉

D.将半球分成两半

E.大脑镰可以增强

题型:选择题

形成胆囊憩室最常见的原因是

A.术后创伤

B.肿瘤

C.外压

D.流出梗阻

E.结石

题型:选择题

一直立的突扩管如图6-11所示,水由上向下流动,已知d1=150mm,d2=300mm,h=1.5m,v2=3m/s,则水银测压计中水银液面的高差为()。

A.0.09mHg

B.0.17mHg

C.0.22mHg

D.0.35mHg

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