WHO提倡的儿童纯母乳喂养时期至少为()
A.2~3个月
B.3~4个月
C.4~6个月
D.6~8个月
E.8~10个月
参考答案:C
—The rescue team are considering ______they can do more for the people suffering from the snow storm.
—So they are.
A.what
B.whatever
C.if
D.how
下列有关酶的叙述不正确的是()
A.所有酶都含有C、H、O、N四种元素
B.酶不一定只在细胞内起催化作用
C.高温、低温、过酸、过碱都会使酶永久性失活
D.一般说来,活细胞都能产生酶