天然水中都含有杂质
参考答案:对
-What would you like for your birthday ? What about an MP5?
-Oh, to tell the truth, I ______ have an I-Pad than an MP5.
A.prefer
B.prefer to
C.had better
D.would rather
免疫球蛋白中相对分子质量最大的是()
A.IgA
B.IgM
C.IgD
D.IgG
E.IgE