—Coach, can I continue with the training?
—Sorry, you can’t you haven’t recovered from the knee injury.
A. until
B. before
C. as
D. unless
网友回答
A. until
B. before
(答案→)C. as
D. unless
解析：此题考查原因状语从句。“教练，我能够继续我的训练吗？”“不行，因为你膝盖的伤还没有痊愈。”后句是现在完成时，要选A或者B，后句要变成肯定句，并使用一般现在时。 “Sorry, you can’t before you recover from the knee injury.”