What do you think ________?

[　　]

A．the most useful invention is

B．is the most useful invention

C．it is the most useful invention

D．is it the most useful invention

What do you think are the most important inventions of the past 2,000 years? The TV? The printing? The telephone? Or the computer? A report shows that these are not the only important inventions. Here are four other important ones.

Paper is one of the most important inventions. You can’t have printing without paper. In 105 AD, Cai Lun invented paper in China. Long before the printing and Internet, Cai Lun’s invention allowed us to write down information, stories and history.

One of the simplest (最簡(jiǎn)單) inventions to save life is the toilet. Before toilets, waste ran into the rivers from people’s houses. Illnesses were common (普通的) in big cities, and it was often difficult to find clean drinking water.

Animal food is another invention. Before the invention, most animals were killed every autumn because there was not enough food for them in the winter. After hay (干草) became a kind of common animal food, animals could live through the long winter.

Reading glasses is the fourth invention. People start getting far-sighted (遠(yuǎn)視) from the age of 45. Glasses mean that anyone can read, write and do “close work” after that age. Without glasses, the world would be difficult for the people above 45.

1.Cai Lun’s invention of paper makes it possible to ______.

A．have printing                           B．feed animals

C．drink clean water                       D．do “close work”

2.The invention of the toilet can stop people from ______.

A．saving water                           B．getting ill

C．living in big cities                        D．finding clean water

3.Why couldn’t the animals live through the winter?

A．It was very cold in winter.                 B．They didn’t have enough food to eat.

C．They had no drinking water.               D．They died of illness.

4.From the last paragraph we learn that ______.

A．a(chǎn)ll people need reading glasses

B．a(chǎn)nyone must do “close work” after 45

C．reading glasses are useful

D．life is more difficult for the people under 45