Get off ____________ the post office. [ ]
A. on
B. with
C. at
答案：C
医生给孕妇做B超，说明声波能够传递 ；医生用超声波粉碎人体内的结石，说明声波能够传递 。
I believe _____ you have made efforts and ______ you are sure to achieve your goal.
A．that; /
B．/; /
C．/; that
D．whether; that
