The plural form of "vertebra" is _____________.

A.stimulus

B.stimuli

C.stimuluses

D.stimula

The electric potential V in a certain region of space is given byin SI. The electric fieldin vector form at point (x,y,z)=(1,2,3) is () in SI.

A、

B、

C、

D、

The students who use dictionaries most do not learn especially well, either. The one who look up every new word do not read fast. Therefore they do not have time to read much. Those who use small two-language dictionaries have the worst problems. Their dictionaries often give only one or two words as a translation of English. But one English word often has many translations in a foreign language and one foreign word has many translations in English.

The most successful students are those who use large college dictionaries with about 100,000 words but do not use them too often. When they are reading, these students first try to get the general idea and understand new words from the context(上下文). Then they reread and use the dictionary to look up only key words that they still do not understand. They use dictionaries more for writing. If they are not sure how to spell a word, or divide it into syllables (音节), they always use a dictionary. Also, if they think a noun might have an unusual plural form. or a verb might have an un- usual past form, they check these in a dictionary.

The writer ends to (倾向) think that ________.

A．choose a good dictionary, and you'll succeed in learning English

B．dictionaries are not very necessary to the students who learn English

C．it is very important for students to use good dictionaries properly

D．using dictionaries very often can't help to improve writing

How are interested customers asked to sign up for this program？

A．By going to a store

B．By visiting a web site

C．By calling the company

D．By faxing an application form