下列哪项决定抗原特异性（）。
A.分子结构
B.抗原决定簇
C.化学组成
D.异物性
E.分子量
参考答案：B
Taking medicine only gives you _______ relief from pain, so I suggest you have an operation.
A．flexible
B．optional
C．temporary
D．beneficial
Mr. Green didn’t understand ________ made his daughter so absent-minded this morning.
A．how that was
B．what was it
C．why it was that
D．what it was that
