【多选题】传染性疾病对实验动物生产和使用带来哪些危害()。
A.
携带人畜共患病原体,直接危害人类和动物的健康
B.
影响动物的生产,烈性传染病可导致整个动物群的毁灭
C.
使整个动物群带毒,带毒群体很难净化,会反复爆发疾病
【单选题】关于血压的生理性变化,错误的叙述是( )。【历年考试真题】
【单选题】The plane was flying normally for about 15 minutes before a warning light started blinking.
【单选题】The plane was flying .
【单选题】The plane was flying so low that it nearly ripped the roof of a house.
A.
to tear away violently
B.
to produce, display, or utter suddenly
C.
to subject to violent criticism or attack