—Did you return Fred's call?—I didn't need to I'll see him tomorrow.A. thoughB. unlessC.

问题补充：

—Did you return Freds call?

—I didn need to Ill see him tomorrow.

A. though

B. unless

C. when

D. because

答案：

A. though

B. unless

C. when

(答案→)D. because

解析：

句意：——你给Fred回电话了吗？——我没必要，因为明天我要去见他。though虽然；unless除非；when当……时；because因为。