雷尼替丁不具备哪个性质（）
A.H2受体拮抗剂
B.含有呋喃环
C.是前药
D.为反式体，顺式体无活性
E.易溶于水
参考答案：C
Fully _____ in looking after three children at home, she no longer has time to enjoy various activities in the club.
A．attached
B．occupied
C．contributed
D．devoted
输送机胶带的接头方法有（）。
A.机械接头法
B.铰接法
C.硫化胶合法
D.夹板法
