【简答题】下列化合物哪些有顺反异构体?A. B. C. D.
【单选题】人们用药的唯一目的,评价药品质量的最重要的指标是()
【单选题】Tom was caught cheating in an important exam. _____, he lost a golden chance of taking part in this competition.
【单选题】—Tom was caught cheating in the exam. —Just his luck. ______
A.
He has to face the music.
B.
He has to kill the fatted calf.
C.
He must be the salt of the earth.
D.
He must be a black sheep.
【判断题】[ ] 遗传密码的简并性是指一个氨基酸可以有几个密码的现象。