在等电点以上的pH溶液中氨基酸带（）
A.正电荷
B.负电荷
C.不带电荷
D.以上都有可能
参考答案：B
有色金属中含有易氧化烧损的合金元素，因此常用的熔炉有( )。
A．坩埚炉
B．平炉
C．电弧炉
D．反射炉
Transformational generative linguists believe that every normal human being was born with an LAD. Here LAD is the short form of ______.
A. learner's acquisition device B. language acquisition deviceC. linguistic acting discussion D. long-term acquiring details
