有H2、O2、CO、CO2四种气体,请选择适当的气体填空. (1)具有可燃性的是

题型:填空题

问题:

有H2、O2、CO、CO2四种气体,请选择适当的气体填空.

(1)具有可燃性的是 _________

(2)有毒的是 _________

(3)能使带火星的木条复燃的是 _________

(4)能使紫色石蕊试液变红的是 _________

(5)能将灼热的氧化铜还原为铜的化合物是 _________

(6)只能用向上排空气法收集的是 _________

(7)可用来灭火的是 _________

考点:二氧化碳的性质氧气的性质氢气的性质一氧化碳的性质和用途一氧化碳的毒性
题型:填空题

一个三位数乘6,所得的积可能是三位数,也可能是四位数.______.(判断对错)

题型:填空题

请从以下选项(A、B、C、D和E)中选出符合各段意思的小标题, 选项中有一项是多余选项。

A. Early to Bed, Early to Rise

B. Read Challenging Books

C. Relax yourself

D. Minimize Television Watching

E. Take Time to Reflect

Five Simple Ways to Increase Your Intelligence

Your brain needs exercise just like a muscle. If you use it often and in the right ways, you will become a more skilled thinker and increase your ability to focus.  

Here are 5 simple ways anyone can squeeze a bit more productivity out of the old gray matter.

小题1:_________-This is a hard sell. People love vegetating in front of the television, myself included more often than I’d like. The problem is watching television doesn’t use your mental capacity OR allow it to recharge. It’s like having the energy sapped out of a muscle without the health benefits of exercise.

When you feel like relaxing, try reading a book instead. If you’re too tired, listen to some music. When you’re with your friends or family, leave the tube off and have a conversation. All of these things use your mind more than television and allow you to relax.

Exercise- I used to think that I'd learn more by not exercising and using the time to read a book instead. But I realized that time spent exercising always leads to greater learning because it improves productivity during the time afterwards. Using your body clears your head and creates a wave of energy. Afterwards, you feel invigorated(精力充沛)and can concentrate more easily.

小题2:_________-Many people like to read popular suspense fiction, but generally these books aren't mentally stimulating. If you want to improve your thinking and writing ability you should read books that make you focus. Reading a classic novel can change your view of the world and will make you think in more precise, elegant English. Don’t be afraid to look up a word if you don’t know it, and don’t be afraid of dense passages. Take your time, re-read when necessary, and you’ll soon grow accustomed to the author’s style.

小题3:_________-Nothing makes it harder to concentrate than sleep deprivation. You'll be most rejuvenated if you go to bed early and don’t sleep more than 8 hours. If you stay up late and compensate by sleeping late, you’ll wake up lethargic(无精打采)and have trouble focusing. In my experience the early morning hours are the most tranquil and productive. Waking up early gives you more productive hours and maximizes your mental acuity(敏锐)all day.

If you have the opportunity, take 10-20 minute naps when you are hit with a wave of drowsiness. Anything longer will make you lethargic, but a short nap will refresh you.

小题4:_________-Often our lives get so hectic that we become overwhelmed without even realizing it. It becomes difficult to concentrate because nagging thoughts keep interrupting. Spending some time alone in reflection gives you a chance to organize your thoughts and prioritize your responsibilities. Afterwards, you’ll have a better understanding of what's important and what isn’t. The unimportant stuff won’t bother you anymore and your mind will feel less encumbered.

Conclusion-I hope you aren’t disappointed that none of the techniques I've proposed are revolutionary. But simple, unexciting answers are often the most valid. The challenge is having the will to adhere to them. If you succeed in following these 5 tips, you’ll be rewarded with increased mental acuity and retention of knowledge.

题型:填空题

在近代科技发展中,技术革新从发明、应用到推广的循环过程不断加快。世界经济的繁荣是建立在导致新产业诞生的连续不断的技术革新上的。因此,产业界需要增加科研投入以促进经济进一步持续发展。

上述论证基于以下哪项假设?()

Ⅰ.科研成果能够产生一系列新技术、新发明。

Ⅱ.电讯、生物制药、环保是目前技术革新循环最快的产业,将会在未来几年中产生大量的新技术、新发明。

Ⅲ.目前产业界投入科研的资金量还不足以确保一系列新技术、新发明的产生。

A.仅Ⅰ

B.仅Ⅲ

C.仅Ⅰ和Ⅱ

D.仅Ⅰ和Ⅲ

题型:填空题

根据技术分析理论,三角形态属于()。

A.持续整理形态

B.反转突破形态

C.三重顶(底)形态

D.头肩形态

题型:填空题

患者,男,27岁,门牙外伤已做根管治疗,片示根充到位,该牙无扣痛,覆覆盖正常,最佳的修复方法是()

A.甲冠修复

B.金属全冠修复

C.烤瓷全冠修复

D.烤瓷桩冠修复

E.树脂修复

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