How can you expect him to make any improvement you never give him an opportunity to have

问题补充：

How can you expect him to make any improvement you never give him an opportunity to have a try?

A. unless

B. when

C. until

D. while

答案：

A. unless

(答案→)B. when

C. until

D. while

解析：考查连词：A．unless 除非，B．when当…时候，既然，如果，C．until直到，D．while即使，虽然，然而，当…时候，句意：既然你不从来不给他任何机会去尝试，你又怎么能够知道他不会有任何的进步呢？选B。