they are fit, I see no reason why they shouldn't go on playing basketball for another four or five years.
A. In case
B. Provided that
C. Unless
D. As if
网友回答
A. In case
(答案→)B. Provided that
C. Unless
D. As if
解析：A. In case以防，万一，B. Provided that假如，条件是，C. Unless 除非，D. As if如果，句意：如果他们是健康的，我看不出他们为什么不应该再打四五年篮球。选B。