问题 选择题

科学证明:空气中的微量臭氧(O3),可抵抗阳光中紫外线对人体的损害。空调和冰箱的制冷剂“氟里昂”是一种氯氟烃(以M代替其化学式),它可破坏臭氧层,其反应过程可表示为: M + O3 → MO + O2 ,MO + O3 → M + O2根据所学知识可知氯氟烃在反应中的作用是:[ ]

A. 催化剂

B. 还原剂

C. 氧化剂

D. 稳定剂

答案

答案:A

阅读理解

阅读短文,判断下列句子正(T)误(F)。

    Tom arrived at the bus station quite early for a bus to Paris. It would not leave until five to twelve.

He saw a lot of people waiting at the station. Some were standing in line, and others were

    walking around.

    There was a group of schoolgirls. Their teacher was trying to keep them in line. Tom looked around

but there was no place for him to sit.

    He walked into a station caff (小餐馆). He looked up at the clock there. It was only twenty to twelve.

He found a seat and sat down before a large mirror on the wall. Just then, Mike, one of Tom's friends,

came in and sat with Tom.

    "What time is your bus?" asked Mike.

    'There is still 15 minutes left," answered Tom.

    "Well, we have enough time to have a cup of tea ,"said Mike.

    They talked while drinking. Then Tom looked at the clock again. "Oh! It's going backward (向后)!"

he cried."A few minutes ago it was twenty to twelve and now it's half past eleven."

    "You are looking at the clock in the mirror ,"said Mike. Tom was sad, because he had to wait for

another bus.

( )1. Tom went into the station caff because Mike asked him to have a cup of tea.

( )2. It was half past one in fact when Tom looked at the clock in the mirror.  

( )3. Mike also waited for the bus to Paris.                                    

( )4. Tom arrived in Paris on time.                                              

( )5. Tom missed (错过) the bus because of the mirror.                          

解答题