—We'll go to the party to be held in Qinghai Grand Theater at 8 tonight. Could you join us

问题补充：

—Well go to the party to be held in Qinghai Grand Theater at 8 tonight. Could you join us?

—Im afraid I can . I the holiday plan with my friends.

A. am discussing

B. have discussed

C. will be discussing

D. will have discussed

答案：

A. am discussing

B. have discussed

(答案→)C. will be discussing

D. will have discussed

解析：C 考察动词时态。句义：我参加不了巨虎，因为今晚8点我讲正合朋友讨论假期计划。Discuss所表示的动作在今晚8点正在进行，应用将来进行时。故C正确。