.Because of the sharp drop of birth rate, the number of students sitting the col

题型：不详难度：来源：

.
Because of the sharp drop of birth rate, the number of students sitting the college entrance exams ______ all the time

A．is declining	B．has declined
C．have been declined	D．were declining

答案

解析

略

举一反三

.
When Bill Gates decided to stop schooling and created Microsoft in 1975, he ______ law at Harvard University.

A．studied

B．had studied

C．was studying

D．would study

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.
If a computer crashes, you will lose the file you _________unless you save it regularly.

A．are working

B．work

C．will work

D．worked

题型：不详难度：| 查看答案

.
To help today’s customers make a choice, a company in New York _____a video trolley — a supermarket trolley with a video screen to display advertisement and price information.

A．has invented

B．had invented

C．invents

D．is inventing

题型：不详难度：| 查看答案

.
In the rainforest of the Amazon, 50 to 150 plant species _____ every day.

A．have been destroyed

B．are destroying

C．are being destroyed

D．destroyed

题型：不详难度：| 查看答案

.
We won’t know how much food to buy until we decide how many people ________.

A．were coming

B．are coming

C．have been coming

D．had come

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