在生态系统中,生产者所制造的有机物,最终消失于[ ] A.初级消费者 B.次级消

题型:选择题

问题:

在生态系统中,生产者所制造的有机物,最终消失于[ ]

A.初级消费者

B.次级消费者

C.三级消费者

D.分解者

考点:生态系统的能量流动
题型:选择题

户外10KV隔离开关允许拉合()KM以下的空载架空线路。

A、1

B、5

C、10

D、20

题型:选择题

河床式水电站一般修建在河流的中下游,水头(),引用流量()。

A.高,大

B.低,大

C.低,小

D.高,小

题型:选择题

My first visit to Angkor Wat(吴哥窟) was in 1980. The country had been at war for many years and the temple was deserted and falling to pieces. Plants were growing out of the roofs, and trees were growing in the courtyards.

Today, the temple is the scene of a busy repair program. A team of 15 Indian experts are organizing a workforce of 400 Cambodians, most of them women, who are cleaning, repairing and rebuilding parts of this temple.

  As I walked through the courtyards, I noticed the Cambodian women devote hours to cleaning carefully a tiny area of stone. Boards are laid down to protect the precious painted stones while the repair work is going on. There are very few machines and little heavy equipment. Workers carry building materials in buckets at the end of long poles. Piles of stones lie in a corner of the courtyard, waiting to be replaced.    

  The work of cleaning the stones is watched over by three Indian chemists. It is a very slow task. First they clean the stones with brushes using buckets of a weak chemical. Then gaps between the stones are filled in. Finally another material is painted onto the stones which will protect them from water forever.

Work starts every day at 7 a. m. and goes on until late afternoon six days a week, with a break at midday.

Evening is the best time to visit the temple, after the tour groups have left. As the sun sinks lower, shadows spread across the courtyard. After sunset, the sky turns pink. The grey stone towers take on a golden color before turning pink. Nowhere else in the world can there be such a quiet, beautiful place.

小题1:This passage mainly tells ________.

A.the poor look of the temple Angkor Wat in 1980

B.the history of the temple Angkor Wat

C.the repair work being done to the temple Angkor Wat

D.the difficulty in the repair work小题2:According to the author, which of the following plays the LEAST important role in the repair work?

A.The women workers.

B.The Indian workers

C.Machines

D.Skilled workers小题3:The underlined sentence “the temple was deserted” possibly means that _______.

A.there was no one in the temple and it was in a poor state

B.the temple was built on desert and nobody noticed it

C.the temple was very old with a long history

D.the temple was repaired by the Cambodians, most of whom women小题4:To clean the stone, how many steps should be followed?

A.Two

B.Three

C.Four

D.Five小题5:Which work needs a lot of time to do?

A.To get rid of certain types of plants.

B.To carry the building materials.

C.To replace the stones.

D.To clean the stones.

题型:选择题

下列说法中,正确的是(  )

A.在相同的时间内做的功越多,机械效率越高

B.在相同的时间内做的功越多,功率就越大

C.功率大的机器,机械效率一定高

D.功率大的机器,做的功一定多

题型:选择题

关于隧道衬砌断面的结构轴线说法正确的有()。

A.当承受径向分布的静水压力时采用圆形

B.当主要承受竖向荷载时上部采用平顶形

C.当同时承受较大竖向荷载和水平荷载时采用下部凸向外方的圆弧形

D.当承受较大底鼓压力时结构底部采用凸向下方的圆弧形

E.当主要承受竖向荷载时下部采用直线形

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