问题 选择题

下列关于草履虫的叙述中,不正确的是(  )

A.具有细胞膜、细胞质和细胞核

B.能通过生殖器官进行繁殖

C.能够趋利避害、适应环境

D.对污水有一定的净化作用

答案

A、草履虫是单细胞动物,只由单个细胞组成,有动物细胞的基本结构:细胞膜、细胞质、细胞核等,不符合题意.

B、草履虫是单细胞动物,只由单个细胞组成,个体微小,全部生命活动在一个细胞内完成,不能形成组织、器官等层次,因此无生殖器官,草履虫靠分裂生殖.符合题意.

C、草履虫是一种动物,能躲避有害刺激,趋向有利刺激,这种生物体对外界刺激作出的有规律的反应,叫生物的应激性.不符合题意.

D、草履虫属于动物界中最原始,最低等的原生动物.它喜欢生活在有机物含量较多的稻田、水沟或水不大流动的池塘中,以细菌和单细胞藻类为食.据估计,一只草履虫每小时大约能形成60个食物泡,每个食物泡中大约含有30个细菌,所以,一只草履虫每天大约能吞食43200个细菌,它对污水有一定的净化作用.不符合题意.

故选:B

阅读理解

阅读理解。

     At one time no one could travel on an English road faster than four miles an hour. That was the law until

1896. A man had to walk in front of a car which could not go faster than the man. At night the man had to

carry a red lamp.

     Once Charles Rolls brought a car from France to England, but he wanted to drive faster than four miles

an hour.In order to have no trouble with the police, he had a talk with some of the police officers, who ordered

their policemen to look the other way when the car came along the road. This was a good plan in the country,

but not so easy to follow in the busy streets of London.

     One night Rolls and some friends started from London on their journey to Cambridge. One of the men

walked in front with the red lamp, but he walked as fast as he could.The police became very interested in walls

and shop-fronts when they heard the car,and not one of them saw it.

     They reached a hill ;but what a waste of time it was to drive down the hill at four miles an hour! Rolls was

getting ready to jump into the car; but then he noticed a policeman who was not looking the other way. The

slow car reached him.

     "Good evening," said the policeman,looking at the car.

     "Good evening," said Rolls,holding the lamp.

     "One of these horseless things," said the policeman, looking at it with interest.

     "Yes," said Rolls, and waited.

     "I've often wanted a ride in one ; but of course policemen can't buy things like that." He turned and looked

hopefully in Rolls's face.

     "Jump in," said Rolls.

     "Thanks," said the policeman,and did so."Now,"he said,  sitting down,"you can let it go just as you like

down this hill. There isn't another policeman on this road for a mile and a half."

1.The policemen were told "to look the other way" (the underlined part in Paragraph 2) so that _____.

A. they could watch the car coming from the other direction

B. the car could go faster than four miles an hour

C. they could make sure no one was in the way

D. the car would not hit them on the road

2. In what way did the policemen carry out the order from their officers?

A. They greeted Rolls when the car came along.

B. They walked in front of the car with a red lamp.

C. They pretended to be attracted by something else.

D. They stood on duty every 1.5 miles along the road.

3. The policeman who said "Good evening" to Rolls wanted to _____.

A. teach Rolls a lesson

B. take a free ride home

C. have a talk with Rolls

D. have a car ride experience

4. After the policeman jumped into the car, Rolls _____.

A. dared not drive the car faster than he was allowed to

B. could drive as fast as he wished within a certain distance

C. could drive on any road he liked for the rest of the journey

D. drove his car as fast as he could down the hill to Cambridge

单项选择题