绒毛膜癌最常见的转移部位是（）A．肝B．阴道C．肺D．消化道E．脑

In their efforts to define "the alcoholic personality", some scientists ______.

A．have identified typical alcoholics

B．have identified preoccupation with self as a cause of alcoholism

C．have found that alcoholics have some characteristics in common

D．have produced an accurate description of a typical alcoholic

their teaching seriously; some get along well with their students; and some have their peculiar characteristics, such as easy-going, warm-hearted or cheerful.

Write an essay making use of the information provided below:

Does brain power ______ as we get older？ Scientists now have some surprising answers.

A．descend

B．decline

C．deduce

D．collapse

e-threatening diseases, such as whooping cough, polio and diphtheria. Therefore, Steven, who has been immunized, is most unlikely to fall sick with these diseases.

Which two characteristics are common in bacteria？ Click on 2 answer choices.

A．They have one cell.

B．They are harmful to humans.

C．They reproduce quickly.

D．They die when exposed to air.

Many human languages of the world have certain common characteristics EXCEPT that

A．humans have a natural, innate ability to acquire and create language.

B．focusing on how to use a language is the fastest way to communicate.

C．language learners learn primarily from their peers, who are also learners.

D．because human languages are changing constantly, so they are fluid.

s. ()

Manyvoiceshave been raised demanding the setting up of an Arab common market. (具体化)

There have been some 2,500 languages in the world.()