—Your colleague is speaking English with fluency.    

—It's no wonder．She ____ in the UK for a year as a visiting professor．

A．worked

B．has worked

C．had worked

D．has been working

平行承包模式缺点之一是( )。

A．不利于质量控制

B．不利于工期控制

C．不利于业主选择承建单位

D．不利于投资控制