活动义齿受力时卡环可随基托下沉刺激牙龈组织，所以不宜单独使用的卡环是
A．邻间沟B．双臂卡环C．正型卡环D．间隙卡环E．对半卡环
参考答案：B
___exceptions, the rule may stand.
A．Allow for
B．Allowing for
C．To allow
D．To allow for
It's eight o'clock Henry _____ the phone. [ ]
A. talks on
B. talks in
C. is talking on
D. is talking in
