A ____ has many teeth, but it can't eat anything.[ ]
A. book
B. comb
C. ball
答案:B
23. Jenny is always _______, never complaining about her poor health and other troubles.
A.careless
B.grateful
C.cheerful
D.comfortable
中毒食物样品的采集应具有()。
A.均匀性
B.时间性
C.典型性
D.广泛性
E.溯源性