_____ is known to all that oil and water don’...

_____ is known to all that oil and water don’t mix up.

高二英语单项填空简单题查看答案及解析

It is well known to all that water, ______ enough, can change into ice quickly．

高二英语单项填空简单题查看答案及解析

It is well known to all that water, ______ enough, can change into ice quickly．

A．if cooling                                            B．though to be cooled

C．when cooled                                       D．when is cooled

高二英语单项填空中等难度题查看答案及解析

What is known to all is that up to now China has made a great___________ to preserving the peace.

A. conclusion　　 　 B. comment

C. campaign　　　　　　 D. contribution

高二英语单项填空中等难度题查看答案及解析

It is well known that _________ air and water are harmful to people’s health.

A. pollute　　　　　　　　 B. polluting

C. to pollute　　　　　　 D. polluted

高二英语单项填空中等难度题查看答案及解析

We all know that water is tasteless. But it happens from time to time: you pick up the bottle of water you didn’t finish yesterday, and it tastes strange. Most often, you tend to drop the bottle in the trash bin, believing that the water has gone bad. But is it true?

According to Time, of course not, taste has little to do with quality of water.

According to Time, when water is exposed to the air for 12 hours, carbon dioxide interacts with the H2O in the water, and the pH value lowers slightly. As a result, the water has a different taste.

“But it’s most likely safe to drink,” Norwegian expert Truls Krogh told Science Nordic. “If the water is covered and of good quality to start with, in principle it can last a thousand years. That’s because when water is fresh, it contains little organic matter. As long as water is held in clean glasses or bottles, no pollutants will enter it to harm our health.”

People in countries like the US, the UK and Australia usually drink tap water. According to Time, if tap water is drunk within six months, the chlorine (氯气) in the water will be enough to kill any bacteria and keep it safe to drink.

However, there are also some exceptions. If you accidentally put your fingers into water or store water in unclean containers day after day, microorganism (微生物) will enter the water.

With the help of surrounding temperature, and sunlight streaming through windows, these microorganisms multiply quickly. Sooner or later, the water will be in the charge of the unfriendly bacteria. And if you drink the water too often, then you’re more likely to be ill.

And what about water in plastic bottles? Heat and plastic are a bad combination, US researcher Kellogg Schwab stresses. When plastic bottles are used at high temperatures, they produce a chemical called BPA. BPA is something that affects hormones (荷尔蒙) and research has tentatively linked it to “several health damage, including heart disease and cancer”, Time reported.

Schwab suggests replacing disposable (一次性的) plastic bottles with the refillable containers made of metal or glass to deal with BPA.

1.The purpose of the first paragraph is to ________________.

A. show an example B. draw a conclusion

C. analyze a phenomenon D. introduce a topic

2.Which of the following may Truls Krogh agree?

A. If the water tastes different, we shouldn’t drink it.

B. The water held in a clean container is likely safe to drink.

C. Although kept fresh, water may still have much organic matter.

D. Covered water can last for a thousand years.

3.What can we infer from the passage?

A. BPA does little harm to our health.

B. Tap water is always safe to drink.

C. Microorganisms are easy to produce in the heat.

D. Disposable plastic bottles have been banned already.

4.What can be the best title of the passage?

A. Why Water is Tasteless B. How to Get Clean Water

C. Does Water Really Go Bad? D. Learn to Protect Water

高二英语阅读理解困难题查看答案及解析

____ is known to all, persistence is a kind of quality and that’s ____ it takes to do anything well.

A. As; which         B. It; which         C. It; what             D. As; what

高二英语单项填空中等难度题查看答案及解析

It is well known to car drivers that red means “stop”, green means “go” and yellow means “hurry up and make that damn light”. Why those colors, though? The answer lies in the fact that the earliest traffic signals were designed for trains, not cars. They were red and green, gas-powered, and more than a little dangerous in the event of a leak.

Red is an inherited (继承的) symbol from railroads, which symbolizes danger in many cultures. As red has a longer wavelength than any other color on the visible spectrum (光谱), it can be seen from a greater distance than other colors. Red has meant “stop” since long before cars existed, with train signals’ use of red dating back to the days when mechanical arms lifted and lowered to indicate whether the rail ahead was clear.

Green’s wavelength is next to (and shorter than) yellow’s on the visible spectrum, meaning it’s still easier to see than any color other than red and yellow. Back in the early days of railway lights, green meant “caution”, while the “all-clear” light was, well, clear or white. It is said that several disastrous collisions happened after an engineer mistook stars in the night for an all-clear. Thus, green became “go”, and for a long time, railways used only green and red to signal trains.

From the earliest days of motoring up until mid-1900s, not all stop signs were red-many were yellow, because at night it was all but impossible to see a red stop sign in a poorly lit area. In 1950 the yellow stop-sign craze began in Detroit, a city that five years later installed its first electric traffic signal, which happened to include the very first yellow traffic light.

But what of those mysterious yellow stop-signs? As materials and technologies evolved, the ability to produce highly reflective signs meant that red could resume its natural spot in the sign hierarchy (层次体系，等级体系), leaving the still-highly-visible yellow to the domain (领域) of “caution”. That’s why school zones and buses, crosswalks, and other important warnings are yellow today.

1.What’s the main reason for the color red’s long being used to mean “stop”?

A.It has the longest wavelength on the visible spectrum.

B.It represents danger in many cultures.

C.It can be seen even in the dark area.

D.People prefer red to other colors.

2.Which of the following may the author agree with?

A.The meaning of red is culture–specific.

B.Yellow functioned as stop signs in the 1900s.

C.Green’s wavelength is just second to that of red.

D.Green’s role in traffic lights has changed over time.

3.What does the passage mainly talk about?

A.The significance of road traffic signs.

B.The history of railroad transportation.

C.The symbolic meaning of different colors.

D.The origin and development of traffic lights.

高二英语阅读理解中等难度题查看答案及解析

____ is known to all, China will be an _____ and powerful country in 20 or 30 years’ time.

A. That; advancing                B. What; advanced

C. As; advanced                  D. It; advanced

高二英语单项填空简单题查看答案及解析

___ is known to all, China will be an _____ and powerful country in 20 or 30 years’time.

A．That; advancing     B．This; advanced      C．As; advanced       D．It; advancing

高二英语单项填空中等难度题查看答案及解析