问题 问答题

请用“左边”或“右边”填写下列空白.

两边同时加入金属后,哪边反应快?______.

两边同时加入固体后,哪边试管璧热______.

 

通电一段时间后,试管里哪边液面高______.

取下镁带点燃后,将生成物全部放回,哪边重?______.

答案

(1)由于在金属活动性顺序中,镁在锌前,因此两种金属和同样的酸溶液反应,镁反应的快,故答案为:左边

(2)由于氢氧化钠固体溶于水放热,而硝酸铵固体溶于水吸热,故答案为:右边

(3)由于水通电分解生成的氢气和氧气的体积比是2:1,因此通电一段时间后,试管里液面高的也就是得到气体少即得到氧气的试管,而氧气在正极上得到,故答案为:右边

(4)由于生成的氧化镁的质量应该等于参加反应的镁和氧气的质量之和,因此反应后的固体比反应前的质量大,故答案为:左边

阅读理解

Spring is here and so is the cycling season. Here are some tips on how to do it safely and comfortably.

Watch your feet—Pushing with the wrong part of the foot can raise your risk of developing a painful injury of the heel and arch(脚心), says Rob Werstine, a sports physiotherapist(理疗师)and board member of the Canadian Physiotherapy Association.  You should push with the ball of your foot, he says.

Layer up—While it’s still cool, wear layers of clothing, with clothing close to the body that breathes and outer layers that do not absorb water. Go for bright colors that increase your visibility(可见度).

Be reasonable—If you are just starting out and aren’t in good shape, don’t sign up for a 50-kilometre ride. And while cycling is great exercise for people who want to get into shape, if your doctor advises you not to do tiring exercise, cycling shouldn't be your starting position, Werstine says. Walk to begin getting into shape and then graduate to cycling.                           

Fix the fit—If you develop lower back pain or numbness in your hands and fingers from cycling, it could be your bike isn’t adjusted properly for your height. A good cycle shop can help you find the right height for the seat and handlebars, but if you have continuing problems, consider consulting a bike fit physiotherapist, Werstine says.

Be mindful—You have to pay attention on the roads to vehicles, other cyclists and pedestrians(行人).Consider taking a cycling safety course to practise your skills. Or do some reading about how to avoid dangerous cycling situations. bicyclesafe.com, for instance, lists 10 types of car-bike accidents and how to avoid them.

小题1:Which part of the foot should one use when cycling?

A.The heel.

B.The arch.

C.The ball.

D.The toes.小题2: From Paragraph 4 we can conclude______.

A.not everyone can exercise by cycling

B.walking is better than cycling

C.cycling is popular with people

D.cycling is helpful to everyone小题3:According to the last paragraph, if you want to avoid danger when cycling, you should ______.

a. consider taking a cycling safety course

b. search for information on bicyclesafe.com

c. consider consulting a bike fit physiotherapist

d. adjust the bike properly for your height

A.a. c

B.c. d

C.a. b

D.b. d

单项选择题 案例分析题