问题 选择题

人们常用节育的方式来进行计划生育,结扎输卵管或输精管的目的是

A.阻碍精子的产生 

B.阻碍卵细胞的产生

C.阻碍精子和卵细胞的结合 

D.阻碍受精卵的发育

答案

答案:C

题目分析:精子与卵细胞受精的场所是在输卵管,精子从 * * 通过子宫,在输卵管与卵细胞相遇而完成受精过程的,把输卵管结扎,这样就阻止了精子与卵细胞相遇因而不能完成受精,从而达到避孕的目的,输精管结扎术是一种男性的永久性节育措施,通过输精管切断、结扎,或采用电凝、栓堵、化学药物等闭塞输精管的内脏,从而阻断了精子的输出而达到避孕的目的。

点评:此题较新颖,稍有一定的难度,解答此题的关键是熟练掌握受精过程。

单项选择题

A good modern newspaper is an extraordinary piece of reading. It is remarkable first for what it contains the range of news from local crime to international politics, from sports to business to fashion to science, and the range of comment and special features (特定) as well, from editorial page to feature articles and interviews to criticism of books, art, theatre and music. A newspaper is even more remarkable for the way one reads it never completely, never straight through, but always by jumping from here to there, in and out glancing at one piece, reading another article all the way through, reading just a few paragraphs of the next.
A good modern newspaper offers a variety to attract many different readers, but far more than any one reader is interested in. What brings this variety together in one place is its topicality (时事性), its immediate relation to what is happening in your world and your locality now. But immediacy and the speed of production that goes with it mean also that much of what appears in a newspaper has no more than transient (短暂的) value.
For all these reasons, no two people really read the same paper: what each person does is to put together out of the pages of that day’s paper, his own selection and sequence, his own news paper. For all these reasons, reading newspapers efficiently, which means getting what you want from them without missing things you need but without wasting time, demands skill and self-awareness as you modify and apply the techniques of reading.

A good newspaper offers a variety to readers because ______.

A. it tries to serve different readers
B. it has to cover things that happen in a certain locality
C. readers are difficult to please
D. readers like to read different newspapers

填空题