—I didn't go to see the doctor yesterday.—But you .A. oughtB. ought toC. ought to beD. oug

问题补充：

—I didn go to see the doctor yesterday.

—But you .

A. ought

B. ought to

C. ought to be

D. ought to have

答案：

A. ought

B. ought to

C. ought to be

(答案→)D. ought to have

解析：其完整形式为ought to have seen the doctor yesterday.表示“昨天本应该去看医生的”。