犬佝偻病主要是由于哪一种维生素缺乏引起()
A、维生素A
B、维生素B
C、维生素C
D、维生素D
参考答案:D
— Excuse me, sir. Is the swimming pool open all day as it used to be?
— _____. only from 6:00p.m to 10:00p.m.[ ]
A.That's right
B.Yes, of course
C.Sorry, I'm not sure
D.Sorry, I'm afraid not
甘草质地坚实,断面略呈纤维性,黄白色,()。
A.粉性
B.角质状
C.油性
D.柔润性