问题 多项选择题

往复泵的扬程受()的影响。

A、欲输送的高度

B、输送液体的密度

C、流量

D、管路阻力损失

答案

参考答案:A, D

阅读理解

The Cave of Lascaux

It was Thursday, September 12,1940.Four French teens were out exploring in the woods off the northern slopes of the Pyrenees.Many years before, an old pine tree fell and left a large hole in the ground.The teenagers were curious and they started to explore the area and fell into one of the most important archeological(考古的) finds of the twentieth century!

There are over a hundred limestone(灰岩) caves in this region of France.Some were inhabited by humans thousands and thousands of years ago.Between 15,000 and 17,000 years ago, humans painted lively creatures such as cows, bulls, horses, and even cats on the walls of the caves.

Why did they mark these walls? Was it to tell a story? Was it to record a famous battle? There are many mysteries and ancient secrets still waiting to be discovered in the cave of Lascaux.There were dots in many of the paintings.What do these dots mean? Were they meant to record time, a calendar? Deep in the cave, there is a drawing of a “birdman”.What does this mean? Was it a place for sacred ceremonies? No one knows for sure.

The actual cave of Lascaux was closed in 1963 due to the overabundance of tourists visiting the site.The carbon dioxide that people were breathing out was causing damage to the fragile(易损的) cave paintings.Up till now the Lascaux cave is still closed for tourists.Only a specialist can visit the cave by a special order that must be made out almost a year in advance.Not more than six persons can enter the cave per day.Two days a week, the cave is completely closed.Due to the great interest of numerous tourists, in 1983 Lascaux Ⅱwas opened for tourism.It is an exact replica of the cave of Lascaux.

小题1:The Pyrenees are the __________ in France.

A.mountains

B.forests

C.rivers

D.caves小题2:What does the underlined word “inhabited” in the second paragraph mean?

A.built

B.explored

C.lived in

D.destroyed小题3:In the author's opinion, the cave paintings are __________.

A.old

B.beautiful

C.easily damaged

D.interesting

单项选择题