水溶性维生素的共同特点为（）。
A.一般有前体物
B.不易吸收
C.会积蓄中毒
D.宜每日供给
E.以上都是
参考答案：D
The opening ceremony is to be held in the lecture hall this afternoon, _____ can seat 400 people.
A．where
B．when
C．that
D．which
经口明视气管插管术最关键是尽量显露声门。()
