PT二次小开关的作用？

Last summer holidays, he went to the countryside and worked together with farmers.In this way

he learnt________from farmers.    [ ]

A. a great many  

B. a great deal

C. scores of  

D. much more

如果整体上市场需求下降，房地产就难以销售出去从而难以变现，进而给房地产投资者带来损失，此风险是房地产投资的( )。

A．经营风险

B．流动性风险

C．财务风险

D．管理风险

医师义务和权利不包括（）

A.承诺治疗效果

B.保证病人平等医疗权

C.保障病人医疗权利的实现

D.促进病人身心健康

E.履行自己的职责

When I saw the notice "Women film extras wanted" in a local newspaper, I jumped at the chance. Since childhood, I had dreamt of being a film star. The casting interview went well, and two clays later I was told that I had been chosen. I was to lose some of my enthusiasm for the idea, however extras are often left in the dark for some time as to which role they will play. Finally , the nature of my role was revealed: I was asked to play a mental hospital patient. Despite my disappointment, I agreed to participate. Then, barely a week later, the day of filming dawned. An 13 of us extras, mainly housewives, were driven to an old hospital. The coffee and tea they served us looked and tasted like cement. Then we were rushed off to make-up. My hair was pinned back and make-up was applied that gave me a pale appearance. Then we just sat in a minibus for a few hours, as the cameras rolled elsewhere.
After the second hour had passed I was becoming bored. I bet stars are never treated like this, I thought. I had expected to be so busy that I hadn’t come prepared for a long wait. Many of the others had brought a book or knitting.
Three hours had now passed. Then at last we were called to do our scenes. When the director came in, we were instructed where to stand and what to do. Along with a few others, I was told to sit at a table and weave baskets. This was not an easy task. The cane (藤条)we had to use was very long. On several occasions my basket fell apart in front of my very eyes. On others I only succeeded in hitting a cameraman in the eye.
Life for the other extras was far from easy. Jean, who was barefoot, had to circle the floor. Poor Alice was asked to pretend to bang her head against the wall. Meanwhile, Veronica swept the floor.
Thankfully, after just a few attempts, the scenes were done. And so my first taste of this" glorious" career was over. Although I found the experience quite interesting. My first screen role will almost certainly be my last.

如何进行高层建筑钢柱的安装与校正？