—Can you guess if they tomorrow? —They will come if they free I think.A. come; will beB.

问题补充：

—Can you guess if they tomorrow?

—They will come if they free, I think.

A. come; will be

B. will come; will be

C. come; are

D. will come; are

答案：

A. come; will be

B. will come; will be

C. come; are

(答案→)D. will come; are

解析：

试题分析: 句意：你能猜得出是否他们明天来吗？我想，如果他们有时间会来的。if如果，主句为一般将来时，if引导的条件状语从句用一般现在时代替一般将来时；if是否，引导宾语从句，时态根据实际情况确定，故选D