在某区域内，所有飞机都应使用当地通报的高度表拨正值，其目的主要是（）.A.清除由于非

阅读短文，选择正确答案。

    To start as a volunteer (志愿者), you could look for an organization (机构) or activity in your area. Some

volunteers sign up for the Peace Corps (和平部队) or other organizations and travel to faraway parts of the

world. But you already have things to do at home. So maybe you should start with a small project.

    Meng Chen is a student in Beijing. He goes to the Forbidden City almost every day. The 20-year-old

volunteers there. He tells visitors about the clocks in the clock gallery (钟表馆).

    Meng is one of around 300 volunteer tour guides in the Forbidden City. One-third of them are university

students. They hang around the palace like other visitors, but with red "volunteer" cards on their clothes.

    Meng said he loves spending time in the buildings where 25 emperors (皇帝) spent their whole lives.

"Every brick has a story to tell," he said.

    But volunteer work is more than fun. Meng has to study for the job. It took him about three months to

remember every detail (细节) of the 176 clocks in the clock gallery.

    And it can be frustrating. (让人泄气的) Often, tourists turn down volunteering guides. "Too many people are

in a rush to finish sightseeing. They don't have time to listen to us," said Shi Hui. He is a university student who

volunteers there.On his first day, Shi walked around for three hours until he found a man in his 50s who was

happy to listen to him.

    "It's always fun to have listeners who are interested in your talk," Shi said.

1. How often does Meng Chen volunteer in the Forbidden City? [ ]

A. Once a month.

B. Almost every day.

C. Twice a week.

D. Almost every weekend.

2. What does Meng Chen do at the clock gallery? [    ]

A. He watches the clocks.

B. He repairs broken clocks.

C. He works at a tour guide.

D. He collects visitors' tickets.

3. We can tell from the story that Meng Chen ______. [ ]

A. enjoys being a volunteer

B. is tired of volunteering

C. is shy and seriou

D. will become a tour guide after graduation

4. Volunteers working in the Forbidden City can be frustrated when _____. [ ]

A. they are not paid enough money

B. people refuse to listen to them

C. they have too much work to do

D. they have to travel far to the Forbidden City

5. The passage is mainly about _____. [ ]

A. where to find volunteer work

B. how to become a volunteer

C. things to pay attention to as a volunteer

D. experiences of some volunteer

败血症患者常见的热型为（）

A.稽留热

B.弛张热

C.间歇热

D.不规则热

E.波浪热

按照现行规定，工程建设过程中建设单位扣留每期工程进度款的（）作为工程质量保证金。

A.5%

B.10%

C.15%

D.20%

流动性最弱的流动资产是（）。

A、现金

B、应收账款

C、存货

D、预付账款

晶闸管的导通条件是（）和控制极上同时加上正向电压。

A、阳极

B、阴极

C、门极

D、栅极