问题 选择题

某有机物6.4 g在O2中充分燃烧,只生成8.8 g CO2和7.2 g H2O。下列说法正确的是(  )

A.该化合物仅含C、H两元素

B.该化合物中C、H个数比为1∶4

C.无法确定是否含氧元素

D.该化合物一定含氧元素

答案

BD

m(CO2)="8.8" g,所以m(C)="2.4" g,m(H2O)="7.2" g,则m(H)="0.8" g,m(有机物)="6.4" g-[m(C)+m(H)]="3.2" g,故该有机物含氧元素,且

阅读理解

阅读下面短文,用括号内所给动词的适当形式填空(必要时加助动词或情态动词)。

     She has never learned any new words by heart but has a vocabulary of more than 10,000 words. She

(1)______(begin) to learn English when she was five and a half. And the most surprising thing is that she

(2)______ (pass) CET-4 (英语四级考试) before she graduated from her primary school. Her name is Liu

Yinong, a 13-year-old Junior One student in the High School Affiliated to Renmin University of China (人大附中).

    Liu (3)______ (ask) to learn English by her mother at the very beginning. Her big success results from her

good learning habits. Since long ago, Liu (4)______(have)the habit of practicing her English listening in the

morning and evening. She usually (5)______(listen) to VAO, BBC, and New Concept English (新概念英语).

As fro her spoken English, she keeps on (6)______(practice)it every Friday at the English Corner. Liu said,

"It's important (7)______(carry) on practicing while learning a foreign language." Now you can understand

why she is so good at English.

    Now, little Yinong (8)______(get) ready for entering Harvard University (哈佛大学). She plans to learn

French and German during her middle school. Then she (9)______(choose) to study another language

(10)______(speak) by smaller group of people. She decides to master (掌握) five languages before studying

in Harvard University.

     "My final goal is to be the Secretary-General of the UN (联合国秘书长). I will make a good preparation

for entering the UN," she said.

单项选择题