问题补充：
—You part in the party on time.
—Sorry，I was delayed by the accident.
A. are to take
B. have supposed to take
C. were to have taken
D. supposed to take
答案：
A. are to take
B. have supposed to take
(答案→)C. were to have taken
D. supposed to take
解析：You were to have taken part in the party.意为“你本来应该参加那次聚会的”。
