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
网友回答
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。