问题 单项选择题 B型题

机体接触甲苯的生物监测指标是()

A.尿中马尿酸的测定

B.尿中甲基马尿酸的测定

C.尿中苯乙醇酸和苯乙醛酸的测定

D.尿中β2-微球蛋白的测定

E.尿中三氯乙酸的测定

答案

参考答案:A

解析:慢性镉暴露引起肾损害时,肾小管吸收功能障碍,引起尿中低分子蛋白增多,其中最具代表性的是β2-微球蛋白。机体吸收的甲苯在体内代谢成马尿酸,大部分由尿排出,是常用的甲苯生物监测指标。机体吸收的苯乙烯在体内可代谢成为苯乙醇酸和苯乙醛酸,由尿中排出。因此,可作为苯乙烯的生物监测指标。机体吸收的三氯乙烯在体内代谢成三氯乙酸,由尿排出。尿中三氯乙酸的浓度与接触外剂量有相关关系,因此已作为生物监测指标。

阅读理解

阅读理解

     My mother through her fine example instilled (慢慢灌输)within me the desire to help others.She taught

me to notice those whom others ignore.

     The railroad tracks (轨道) were within a mile of our house.Beggars frequently would knock at the

doors in our neighbourhood in summer asking for food.They were often turned away.Others simply

ignored the knocks.

     My mum always went to the door smiling.She would invite them to stay and have something to eat.She

would have me open up the card table and carry a chair out onto the covered side porch (走廊).There

was a nice view into the flower gardens,and it was cool even on the hottest days.

     She would bring a red and white tablecloth and set the table as carefully as she did for any company.

She would pour their coffee and pile their plates with food and dessert.Usually she sent a packed lunch

with them when they were ready to go,too.Sometimes she would take the newspapers to those who asked

about work.

     She listened to those who wanted to talk.She never asked what would lead them to be in this difficult

situation.It did not matter.She saw only the need.Some thought she should not extend this courtesy

(礼貌).She would say,"In the depression (萧条时期) when my father was searching around for any

work to feed us,thoughtful people fed him.I am just repaying their kindness.I cannot offer them money,but

I can see they do not leave hungry and discouraged." My mum was quite a lady.

1.The writer's house was frequently visited by beggars because________.

A.they seemed to be very rich

B.his mother was known to be generous

C.they lived near a railway station

D.there was a railway near their house

2.How did the writer's mother treat beggars?

A.She was on guard against them.

B.She looked down upon them.

C.She respected them equally.

D.She took pride in them.

3.The writer's mother sometimes took out newspapers________.

A.for the beggars to kill time

B.to teach the beggars how to read

C.to help the beggars who asked about work

D.to help the beggars to find their families

4.Which of the following can make an explanation for the mother's attitude to beggars?

A.Her father was once helped by others.

B.Her father liked to help beggars.

C.She was once a beggar herself.

D.Her mother taught her to help beggars.

单项选择题