At first there were only silent films, but in 1928 sound films were introduced, ______ the characters talk as well as act.
A. on which
B. of whom
C. in which
D. about which
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Most people can’t get ______ the day without at least one cup of tea or coffee.
A. on
B. through
C. over
D. by
Turning the following sentence into the passive voice: According to them, only two tribes used to speak the ancient language of Aramaic.
关于直喉镜和弯喉镜的描述，正确的是
A. 直喉镜必须在标准头后仰位下操作
B. 弯喉镜可以在标准头后仰位下操作
C. 弯喉镜片顶端抵达舌根与会厌交界处，上提喉镜以显露声门
D. 直喉镜顶端越过会厌的喉侧面，上提喉镜直接挑起会厌显露声门
E. 直喉镜和弯喉镜在操作上没有什么不同
受体的特点有
A. 受体大多数是蛋白质、酶等
B. 在机体内有特定的分布
C. 其数量受疾病的影响
D. 与配体结合有特异性和可逆性等特点
E. 受体按与之结合的递质命名
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