问题补充：
I am too busy now. If I free, I to the cinema with you.
A. am; will go
B. am; would go
C. were; would go
D. was; was going
答案：
A. am; will go
B. am; would go
(答案→)C. were; would go
D. was; was going
解析：C if从句用的是虚拟语气，与现实（很忙）相反时，虚拟语气用一般过去时，be统一用were，主句用would do sth.
