To plant a tree，we must dig .
A. a three feet deep hole
B. three-foot deep a hole
C. a hole three feet deep
D. a three-feet-deep hole
网友回答
A. a three feet deep hole
B. three-foot deep a hole
(答案→)C. a hole three feet deep
D. a three-feet-deep hole
解析：three feet deep作a hole的后置定语，不能作前置定语，作前置定语应该说：a three-foot-deep hole。