问题补充：
Mary is very clever and worth teaching , but her brother is not .Look ,he is now asleep in class .
A. very ; very
B. much; very
C. well; very
D. well；fast
答案：
A. very ; very
B. much; very
C. well; very
(答案→)D. well；fast
解析：考查固定搭配。固定搭配be well worth doing 值得做某事；用副词fast修饰形容词asleep.句意：Mary非常聪明，值得教，但是她的兄弟却不是这样。看现在课堂上他就要睡着了。故D正确。
