-- I'd like to invite you to a party tom
问题:
-- I'd like to invite you to a party tomorrow evening.
-- Thank you, but ______ I'll be free I'm uncertain.
A.while
B.if
C.when
D.whether
-- I'd like to invite you to a party tomorrow evening.
-- Thank you, but ______ I'll be free I'm uncertain.
A.while
B.if
C.when
D.whether