问题 选择题

考古学家是通过测定古生物遗骸中碳-14含量来推断它的生活年代.下列关于碳-14原子的说法中,错误的是(  )

A.中子数为6

B.质子数为6

C.电子数为6

D.质子数和中子数之和为14

答案

A、核电荷数=质子数,核电荷数为6,则质子数为6;相对原子质量为14,则中子数为14-6=8,故选项说法错误.

B、根据核电荷数=质子数,碳-14原子的核电荷数为6,则质子数为6,故选项说法正确.

C、根据核电荷数=质子数=核外电子数,碳-14原子的核电荷数为6,则电子数为6,故选项说法正确.

D、根据相对原子质量=质子数+中子数,相对原子质量为14,故质子数和中子数之和为14,故选项说法正确.

故选A.

单项选择题 A1型题
完形填空

阅读下面短文,回答文后的5个问题,并把答案写在答题卡指定区域内。

[1] If you read a newspaper or listen to a newscast(news report) recently, you may hear or read a strange word, “staycation.” Staycation is a new word the American press(newspapers, radio, and television) is using to describe a vacation very close to your own home, or simply staying at home during your vacation. It is a combination of the words “stay” and “vacation”.

[2] According to many news reports, these staycations are very popular among American families this year. Why? The high price of gasoline for cars and airplanes has made it very expensive for Americans to travel compared to past years. When you combine this with the weak American dollar, it all adds up to people deciding to stay close to home during their traditional summer vacations. Of course, some places are more interesting to “stay home at” than others. And if you live in a very small town, well, you may just want to skip your vacation and save your time up to next year!

[3] Everything is expensive nowadays, and let’s face it—a vacation just may not be in your plan this year. You don’t have to give up family fun just because you can’t              ; instead, follow my tips for an economical staycation filled with old favorites and new adventures! Staycations have achieved high popularity in current hard economic times in which unemployment levels and gas prices are high. 

小题1:What is this passage mainly about? (within one word)

小题2:Which two words make the new word “staycation”? (within 3 words)

小题3:What’s the meaning of “staycation”? (within 20 words)

小题4:Why are staycation popular this year? Please list two reasons. (each within 5 words)

小题5:Please fill in the blank with a phrase in the last paragraph. (with 3 words)