问题 选择题

已知两圆的半径分别为7和4,当圆心距从11缩小到3时两圆的位置关系的变化是(  )

A.从相离到相交

B.从相交到相切

C.从外切到内切

D.从外离到内切

答案

因为两圆的半径分别为7和4,7+4=11,

所以当圆心距是11时,位置关系是外切,

7-4=3,当圆心距是3时,位置关系是内切,

故当圆心距从11缩小到3时两圆的位置关系的变化是从外切到内切.

故选C.

单项选择题
单项选择题

In our society, we must communicate with other people. A great deal of communicating is performed on a person-to-person (1) by the simple means of speech. If we travel in buses, stand in football match (2) , we are likely to have conversations (3) we give information or opinions, and sometimes have our views (4) by other members of society.

Face-to-face contact is (5) the only form of communication, and during the last two hundred years the (6) of mass communication has become one of the dominating factors of contemporary society. Two things, (7) others, have caused the enormous growth of the communication industry. Firstly, inventiveness has (8) advances in printing, photography and so on. Secondly, speed has revolutionized the (9) and reception of communications so that local news often (10) a back seat to national news.

No longer is the possession of information (11) to a privileged minority. Forty years ago people used to (12) to the cinema, but now far more people sit at home and turn on the TV to watch a program that (13) into millions of houses. Communication is no longer merely concerned (14) the transmission of information. The modern communications industry influences the way people live in society and broadens their horizons by allowing (15) to information, education and entertainment. The printing, broadcasting and advertising industries are all (16) with informing, educating and entertaining. (17) a great deal of the material communicated by the mass media is very valuable to the individual and to the society (18) which he is a part, the vast modern network of communications is (19) to abuse. However, the mass media are with us for better, for worse, and there is no turning (20) .

11()

A.prohibited

B. provided

C.allowed

D. confined