中国共产主义青年团高举()旗帜,坚决维护和发展()之间的团结友爱。
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某药物与受体相结合后,能激动受体产生某种作用并引起一系列效应,该药属于()
A. 兴奋剂
B. 激动剂
C. 抑制剂
D. 拮抗剂
E. 以上都不是
工作场所的设备、工具、用具等设施应当符合保护劳动者生理、心理健康要求。()
A. 正确
B. 错误
Which of the following statements represents the main difference between a relay and a contactor?()
A. Contactors control current and relays control voltage
B. A relay is series connected and a contactor is parallel connected
Contactors can handle heavier loads than relays
D. Contactors are made from silver and relays are made from copper