Question

【題目】 Flights are often canceled for many different reasons, including snow, clouds, or even a bird getting caught in an airplane’s engine (發(fā)動機(jī)). But you’d never think that too much sunshine would stop a plane from taking off.

Unluckily for passengers in Phoenix, US this summer, their travel plans went dead when more than 40 flights in and out of the local airport were cancelled after temperatures went as high as 48°C. This is the highest temperature that many smaller planes are allowed to fly at.

So what is it that makes flying in great heat so dangerous? The answer lies in how “thick”, the air is.

“As air warms up, it expands (膨脹), and there’s fewer molecules (分子) under your wings,” Lou McNally, a professor at Embry-Riddle Aeronautical University in the US, told the Associated Press (AP).

When the temperature is high and the air becomes thin, “you need more of everything. You need more thrust (推力) to take off. You need more distance to take off. You need more distance to land. It gets to a point for some aircraft that it gets just too much,” McNally explained.

The US’ Southwest, where Phoenix is located, is experiencing an unexpectedly hot summer. This June was its third-hottest on record. According to The Guardian, up to 10 people are thought to have died as a result of the hot weather.

The unexpected heat attacked airlines(航空公司) too, causing them to cancel all flights running on smaller planes for the safety of their passengers.

But what about cities whose temperatures are high every summer?

Many airlines in hot Gulf countries such as the United Arab Emirates make many flights at night or in the early morning to avoid the problem of thin air, according to AP. They also mainly use larger planes, which are able to fly in greater heat than smaller planes.

After the temperature in Phoenix continued to climb over 40°C all through the rest of the summer, maybe now would be a good time for airlines to buy bigger planes in time for next year’s heat wave.

【1】When the weather is too hot, ______.

A.planes are more likely to break down

B.planes need more power and distance to take off

C.there is much more air under the wings of a plane

D.it takes less time for planes to take off and land

【2】How do airlines in Gulf countries deal with high temperatures?

A.They make many flights at midday.

B.They mainly use small planes.

C.They build long runways for planes.

D.They make fewer flights at midday.

【3】What’s the article mainly about?

A.Flight accidents caused by great heat.

B.Perfect flying conditions for aircraft.

C.How dangerous the flights are in hot weather.

D.How hot weather influences flights.

Answer 1

【答案】

【1】B

【2】D

【3】D

【解析】

文章主要說明了溫度影響飛行的原因，以及高溫地區(qū)如何解決這一問題。

【1】細(xì)節(jié)理解題。根據(jù)“When the temperature is high and the air becomes thin, “you need more of everything. You need more thrust （推力）to take off. You need more distance to take off.”可知，高溫時需要更多推力，更長的距離來起飛。故選B。

【2】細(xì)節(jié)理解題。根據(jù)“Many airlines in hot Gulf countries such as the United Arab Emirates make many flights at night or in the early morning to avoid the problem of thin air”可知，為避免高溫，海灣國家航班更多在夜里或清晨，減少中午的飛行次數(shù)。故選D。

【3】主旨大意題。根據(jù)第一段“But you’d never think that too much sunshine would stop a plane from taking off.”可知，文章主要說明高溫如何影響飛機(jī)飛行。故選D。