2019年mba考试英语模拟题——连词843

{01}—  I wonder how much you charge for your services．
— The first two are free ____  the third costs $30．
[      ]
A.while      
B.until
C.when      
D.before
解析：
本题选A。

{02}Find ways to praise your children often，________you’ll find they will open their hearts to you.
A.till  
B.or  
C.and  
D.but

解析：
本题选C。