Question

Do you drink water that’s been left sitting out overnight or even for another day? Have you noticed it tastes different?

Tap water(自来水) that has been left to sit out slowly begins to get an off taste. Many people think that this is because of microorganisms(微生物). But that’s not what makes old water taste not fresh. For that we can think of carbon dioxide(二氧化碳). After about 12 hours, tap water starts to go flat as carbon dioxide in the air starts to mix with the water in the glass, lowering its PH and giving it an off taste. But it's most likely not harmful to drink.

However, back to those microorganisms. If you use a dirty glass day after day, there will be more chances to get bacteria(细菌). The risk will increase if you share the glass with another mouth as well. But supposing you use a fresh glass every few days, you probably won't have a problem unless the glass has been touched by dirty fingers, and especially if those dirty fingers went unwashed after using the bathroom.

As for plastic water bottles that have been left out in the sun or in the car, step away from the bottles, warns Dr. Kellogg Schwab, director of the Johns Hopkins University Water Institute. “A chemical named biphenyl-A, or BPA, along with other things used to make plastic can leach(过滤) into your water if the bottle heats up or sits in the sun,” he explains. BPA, as you probably know, has been linked to everything from serious heart problems to cancer. Schwab also adds that plastic used for commercial bottled water isn’t supposed to be washed or refilled, so use only one time and recycle. Or don't buy them at all; use refillable water bottles instead.

1.Tap water begin to have an off taste because of______.

A.carbon dioxide B.BPA C.the glass D.the microorganism

2.According to Paragraph 2, tap water that's been left sitting out for 12 hours__________.

A.has few microorganisms B.is still safe to drink

C.tastes better than before D.is likely undrinkable

3.According to Paragraph 3, what is the right way to drink with a glass?

A.To share the glass with another person. B.To hold the clean glass with dirty hands.

C.To keep your hands and glass clean. D.To drink after using the bathroom.

4.What should we do with plastic water bottles that are left out in the sun or in the car?

A.Use them after they cool down. B.Clean them and use them again.

C.Throw the bottles away. D.Refill them with fresh water.

5.Which of the following is true about BPA?

A.It is safe for people to use.     B.It is a kind of new material.

C.It is the main material to make plastic. D.It can cause great harm to people.

Answer

1.A

2.B

3.C

4.C

5.D

【解析】

本文介绍日常饮用水安全。解释了隔夜静置自来水味道改变的原因，以及玻璃瓶装水与塑料瓶装水的饮用安全知识。

1.

细节理解题。根据文中But that’s not what makes old water taste not fresh. For that we can think of carbon dioxide可知，导致放的太久的水不新鲜的原因是二氧化碳，故选A。

2.

细节理解题。根据文中After about 12 hours, tap water starts to go flat as carbon dioxide in the air starts to mix with the water in the glass, lowering its PH and giving it an off taste. But it's most likely not harmful to drink.可知，饮用水放置12个小时喝起来还是健康的，故选B。

3.

细节理解题。根据文中If you use a dirty glass day after day, there will be more chances to get bacteria(细菌). The risk will increase if you share the glass with another mouth as well. But supposing you use a fresh glass every few days, you probably won’t have a problem unless the glass has been touched by dirty fingers, and especially if those dirty fingers went unwashed after using the bathroom.可知，用杯子喝水的正确方式是既要杯子干净同时手也要干净，故选C。

4.

细节理解题。根据文中As for plastic water bottles that have been left out in the sun or in the car, step away from the bottles, warns Dr. Kellogg Schwab可知，Dr. Kellogg Schwab警告我们要扔掉长期在阳光下或汽车里放置的塑料瓶，故选C。

5.

细节理解题。根据文中he explains. BPA, as you probably know, has been linked to everything from serious heart problems to cancer.可知，Dr. Kellogg Schwab指出BPA是一种与心脏病和癌症有关的化学物质，由此可以知道，BPA会对人造成极大的伤害。故选D。