we need to dig a ( )hole to plant the tree.
问题描述:
we need to dig a ( )hole to plant the tree.
A.Three feet deep B.three foot deep C.three-feet-deep D.three-foot-deep
答
D.在句中作定语数字+单位(单数)+形容词
就如three years old是表语
three-year-old是定语