只有当H1受体拮抗剂的两个芳环Ar1和Ar2（）时，药物才具有较大的抗组胺活性，否则，活性很低。
A.共平面
B.平行
C.不共平面
D.垂直
参考答案：C
The matter __________ your fate can't be taken for granted. You have to think it over seriously.
A．relates to
B．related to
C．relate to
D．to relate to
The classroom can ___ more than fifty students.
A, have B. take C. hold D. keep
