F．or many years, people electric cars. However, making them has been more difficult than predicted.

A．had dreamed of

B．have dreamed of

C．dreamed of

D．dream of

Electric cars are different from usual cars. They are powered by batteries（电池）.T

We are now able to print things such as clothing, musical instruments and even c

[单选题]Passage FourMany people want to know how to analyze problems they meet. There are six stages in analyzing a problem.F．irst the person must recognize that there is a problem. For example, Sam's bicycle is broken, and he cannot ride it to class as he

[主观题]D．uringtheeightyearswar，manypeople_______theirbloodfortheircountry.A.shedB.temptedC.reservedD.devoted

The Sunday papers are full of for cars.(advertise)The Sunday papers a

Many people hope that the whole world will one day speak a common language.Over

[单选题]For many years, people have tended to think of natural resources as stacks

[单选题]For many years, people have tended to think of natural resources as stacks

[单选题]For many years, people have tended to think of natural resources as stacks

[单选题]For many years, people have tended to think of natural resources as stacks