问题 填空题

如图是小明用电流表测量通过灯泡电流的实验装置图,其中导线a端没有连接.如果小明把导线a端与接线柱b连接,开关闭合时能正常测出通过小灯泡的电流,开关断开时能使电路断开.小明还想做以下尝试,请你帮助他预计会出现什么情况:

①如果把导线a端与接线柱c连接,预计出现的情况为: _________

②如果把导线a端与接线柱d连接,预计出现的情况为: _________

③如果把导线a端与接线柱e连接,预计出现的情况为: _________

答案

①开关没有接入电路中,不能控制电路,所以会出现的情况为:灯泡一直在发光,电流表有示数;

②开关没有接入电路中,不能控制电路,所以会出现的情况为:灯泡一直在发光,电流表有示数;

③电流表相当于一根导线,造成电源短路,会出现的情况为电流过大,可能会烧坏电流表和电源.

阅读理解

Shopping green can make an important contribution to protecting the planet and conserving its resources.

Today’s consumer faces a wider range of choices than ever before, Add to that the steady stream of sales campaigns, and shopping smart only gets harder. To buy economically and reduce waste, safeguard health and protect the environment, you’ll need to follow some basic principles and have a clear idea of what you want.

1. Do Your Homework

Before making any major purchase, take the time to research it. Plentiful resources are usually available online. Avoid buying in a hurry, and don’t be persuaded by overenthusiastic salespeople. Sleep on it if necessary—you won’t regret giving yourself some extra time to think.

2. Take the Long View

Consider the running costs as well as the initial price of any item you buy. Many environmentally friendly products cost more to buy, but save you money in the long run. Choose items that are made to last. For example, pick a sofa that has a hardwood or steel frame rather than one made of softwood, which may break easily.

3. Skip the Disposable Option

Buy reusable products like washable cloth towels, handkerchiefs, serviettes(餐巾)and cleaning cloths rather than paper, single-use varieties. Avoid other disposable supplies like cups, glasses, and chopsticks, too.

4. Take the Local Route

Buy local products that are in season. It’s usually cheaper and fresher and has less harm to the environment. Markets and roadside stands are good sources. Some supermarkets also buy from local producers. Support it if you have one.

5. Avoid Wasteful Packaging

Better not buy products that have too much packaging. It’s estimated that approximately 10 percent of every shopping bill is actually paying for packaging—which you normally just throw away! Moreover, significant amounts of energy are used in the production of packaging. Purchasing refillable and renewable containers can also help cut this kind of waste.

小题1:What could be the best title for this passage?

A.Protection of the Planet

B.Green Shopping Principles

C.Environmentally Friendly Products

D.Resource Conservation小题2:The underlined phrase “sleep on it” has the similar meaning with      .

A.think it over

B.forget about it

C.set it aside

D.put it into action小题3:Why does the author advise us to buy lasting products?

A.Because they are less expensive to buy.

B.Because they save money in the long run.

C.Because they will never break.

D.Because they are local products.小题4:Which of the following can be considered green shopping?

A.Following the stream of sales campaigns.

B.Buying disposable chopsticks.

C.Focusing on packaging.

D.Purchasing from local markets.

单项选择题