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问题 问答题 简答题

简述胶带输送机的七大保护。

答案

参考答案：

（1）防跑偏保护；（2）煤雾保护；（3）温度保护；（4）堆煤保护；（5）防爆保护；（6）防撕裂保护；（7）低速保护。

单项选择题

同位素60CO的半衰期是（）。

A.5.5年

B.5.7年

C.5.3年

D.6年

E.2年
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单项选择题

Mr. Faugel was convinced that student nervousness had affected their scores; to reduce the anxiety of these students who had already been tested, he gave 22 of them a beta blocker before readministration of the test. Their scores improved significantly. The other 8 students (who did not receive the beta blockers) improved only slightly. Second-time test-takers nationwide had average improvements which were similar to those in Faugel’’s non-beta blocker group. Beta blockers are prescription drugs which have been around for 25 years. These medications, which interfere with the effects of adrenalin, have been used for heart conditions and for minor stress such as stage fright. Now they are used for test anxiety. These drugs seem to help test-takers who have low scores because of test fright, but not those who do not know the material. Since there can be side effects from these beta blockers, physicians are not ready to prescribe them routinely for all test-takers.

Beta blockers work on some physical and emotional symptoms because they________.

A．fool a person into a healthier stance

B．interfere with the effects of adrenalin

C．produce side effects worse than the symptoms

D．primarily change human thought processes
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