问题 问答题

BTB是一种酸碱指示剂,BTB的弱碱性溶液颜色可随其中CO2浓度的增高而由蓝变绿再变黄。某同学为研究某种水草的光合作用和呼吸作用,进行了如下实验:用少量的NaHCO 3和BTB加水配制成蓝色溶液,并向溶液中通入一定量的CO2使溶液变成浅绿色,之后将等量的绿色溶液分别加入到7支试管中,其中6支加入生长状况一致的等量水草,另一支不加水草,密闭所有试管。各试管的实验处理和结果见下表。

*遮光是指用黑纸将试管包裹起来,并放在距日光灯100cm的地方。

若不考虑其他生物因素对实验结果的影响,回答下列问题:

(1)本实验中,50min后1号试管的溶液是浅绿色,则说明2至7号试管的实验结果是由引起的;若1号试管的溶液是蓝色,则说明2至7号试管的实验结果()(填“可靠的”或“不可靠的”)。

(2)表中X代表的颜色应为()(填“浅绿色”、“黄色”或“蓝色”),判断依据是()。

(3)5号试管中的溶液颜色在照光前后没有变化,说明在此条件下水草。

答案

参考答案:

(1)不同光强下水草的光合作用和呼吸作用、不可靠的

(2)黄色、水草不进行光合作用,只进行呼吸作用,溶液中CO2浓度高于3号管

(3)光合作用强度等于呼吸作用强度,吸收与释放的CO2量相等

阅读理解

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第三部分:阅读理解(共两节,16小题;每小题2分,满分32分)

第一节:阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

People enjoy talking about “firsts”. They like to remember their first love or their first car. But not all firsts are happy ones.

One of history’s bad but important firsts was the first car accident. Cars were still young when it happened. The accident took place in New York City in May 1896. A man from Massachusetts was visiting the city in his new car. At that time, bicycle riders were still trying to get used to the new set of wheels on the road. No one was sure who was to blame for it. Anyway, the bike and the car hit each other hard. The man on the bike was injured. The driver of the car had to stay in jail and wait for the hospital report on the bicycle rider. Luckily, the rider was not killed.

Three years later, another car accident took place. It was again in New York City. A man named Henry Bliss stepped off a streetcar(无轨电车). He was hit by a passing car. Once again, no one was sure just how it happened or whose fault it was. The driver of the car was put in prison. Poor Mr. Bliss became the first person to die in a car accident.

46. Which of the following is true?

A. The first driver came from New York City.

B. Both of the two car accidents killed a person.

C. The second car accident didn’t happen in the same city as the first one.

D. No one knew how the two accidents had happened.

47. In both accidents the drivers of the cars_______.

A. could not drive their cars very well

B. had to stay in prison for a while

C. tried to run away after the accidents took place

D. knew it was their fault

48. The word “jail” in this passage means ________.

A. police station      B. prison                C. school       D. office

49. The main idea of the passage is ________.

A. not all firsts are happy ones                           B. two of the first car accidents

C. two unhappy “firsts”                             D. bicycle riders get used to cars

单项选择题