| We sometimes think humans are uniquely
vulnerable to anxiety, but stress seems to affect the immune defenses of lower
animals too. In one experiment, for example, behavioral immunologist (免疫学家) Mark
Laudenslager, at the University of Denver, gave mild electric shocks to 24 rats.
Half the animals could switch off the current by turning a wheel in their
enclosure, while the other half could not. The rats in the two groups were
paired so that each time one rat turned the wheel it protected both itself and
its helpless Partner from the shock. Laudenslager found that the immune response
was depressed below normal in the helpless rats but not in those that could turn
off the electricity. What he has demonstrated, he believes, is that lack of
control over an event, not the experience itself, is what wakens the immune
system. Other res A. was altered B. was strengthened C. was weakened D. was not affected [填空题]在关系数据库中，把数据表示成二维表，每一个二维表称为（）。
[填空题]按《地表水和污水监测技术规范》（HJ/91-2002），现场采集的水样分为瞬时水样和混合水样，其中混合水样分为（）和（）。
[单项选择]除法律另有规定外，违法行为在多长期限内未被发现的，不再给予行政处罚
A. 1年 B. 6个月 C. 4年 D. 2年 E. 3年 [单选题]下列设备中（ ）是分组型终端。
A.装有X.25规程的计算机 B.VT系列终端 C.键盘打印机 D.可视图文终端 [单选题]配砟车用旁路制动开关施行制动,制动缸压力由零升至340kPa的时间不大于( ) s。
A.3 B.4 C.5 D.7 [单选题]十八大报告提出，科学发展观的最为鲜明的精神实质是（ ），实事求是，与时俱进，求真务实。
A.凝聚实力 B.世界接轨 C.不断发展 D.解放思想 [单选题]是在制动时将原来驱动轮对的自励牵引电动机改变为他励发电机。
A.备用制动 B.再生制动 C.辅助制动 D.紧急制动 我来回答: 提交
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