问题 选择题

植物在白天吸收入二氧化碳,释放出氧气,而在夜间吸入O2,呼出CO2,这是因为白天(  )

A.日光下进行光合作用,呼吸作用停止

B.光合作用强于呼吸作用

C.呼吸作用在夜间进行,光合作用在夜间进行

D.叶片进行光合作用,不进行呼吸作用

答案

植物有两种对大气效果相反的作用:光合作用和呼吸作用.光合作用吸收二氧化碳放出氧气,同时把光能固定在体内的有机物中.呼吸作用就是吸入氧气参与有机物的分解,释放放出二氧化碳同时释放出能量,供细胞的各项生命活动利用.在白天,光合作用和呼吸作用都在进行,由于光合作用产生的氧气比呼吸作用消耗的氧气多,所以植物在白天可以向外界供氧.在晚上,由于没有光,只进行呼吸作用不能进行光合作用,所以就只能吸入氧气放出二氧化碳.

故选:B

解答题
阅读理解

On a Friday night, a poor young artist stood at the gate of the New York railway station, playing his violin. The music was so great that many people stopped to put some money into the hat of the young man.

The next day, the young artist came to the same place, and put his hat on the ground gracefully. Different from the day before, he took out a large piece of paper and laid it under his hat. Then he began to play the violin. It sounded more pleasant than ever.

Soon he was surrounded with people who were attracted by the words on that paper. It said, “Last night, a gentleman named George Sang put an important thing into my hat by mistake. Please come to claim (认领) it soon.”

After about half an hour, a middle-aged man rushed through the crowd to the violinist and said, “Yes, it’s you. I knew that you were an honest man and would certainly come here.” The young violinist asked calmly, “Are you Mr George Sang?” The man nodded. The violinist asked, “Did you lose something?” “It’s a lottery ticket,” said the man. The violinist took out a lottery ticket on which George Sang’s name was seen. “Is it?” he asked. George nodded and took the lottery ticket and kissed it, then danced with the violinist.

The violinist was a student at an arts college and had planned to attend advanced studies in Vienna. Later his classmate asked the violinist, “At that time you needed money to pay the tuition (学费)and you had to play the violin in the railway station every day to make money. Why didn’t you keep the lottery ticket for yourself?”

The violinist said, “Although I don’t have much money, I live happily. But if I lose honesty I won’t be happy forever.” Through our lives, we can gain a lot and lose so much. But being honest should always be with us.

小题1:What did the young artist do at the railway station on Friday?

A.He played the violin to make some money.

B.He waited for the train to Vienna.

C.He came to buy a train ticket to Vienna.

D.He walked around the New York railway station.小题2:According to the words on the paper, which sentence below is TRUE?

A.It asked a gentleman named George Sang to claim his hat.

B.It asked a gentleman named George Sang to claim his important thing.

C.It was a lottery ticket and he needed to find the owner.

D.It was a lottery ticket and the owner is unknown.小题3: From this article, we can learn that ____.

A.we should share with others if we find something valuable

B.we should know the importance of honesty and lead a happy life

C.keep the lottery if you find one

D.playing the violin could make you feel happy