某机械的效率为50％，表示该机械做功时，功在功中的比例为50％。使用任何机械时．

试述电气设备验电操作顺序？

Kofi Annan says helping survivors of last week’’s earthquake and (1)________in the Indian Ocean is (2)________. The United Nations secretary-general says countries that have offered aid must (3)________and provide it. The offers add up to around (4)________dollars. United Nations officials say (5) ________of that is needed during the next six months.The concern about offers of international aid is (6)________. For example, the earthquake in Bam, Iran, in (7)________of 2003 killed more than (8) ________people. Countries and groups offered hundreds of millions of dollars (9) ________. The United Nations says it has (10)________only about (11)________dollars in aid received so far. Governments and organizations that offered help (12) ________that, however.On (13)________Mr. Annan met with world leaders in Jakarta, Indonesia to discuss aid for (14)________. The leaders discussed and (15)________the idea of (16)________owed by affected nations. But the leaders did not say they would do so. Some said that (17)________to survivors would be more helpful.Representatives of (18)________countries and international organizations attended the meeting in Jakarta. Officials say they will cooperate to develop (19)________ for the Indian Ocean and the (20)________.

脊髓空洞症的感觉障碍是（）。

A.节段型

B.传导束型

C.分离性节段型

D.混合型

E.以上均不是

人体内有效循环血量的丧失达下列哪项时，机体将无法代偿而出现休克的临床症状（）

A.＞5%

B.＞8%

C.＞10%

D.＞20%

E.＞40%

电梯改造中若更换曳引机、控制柜、限速器、门机系统，在验收时必须提供其合格证和检验报告。