问题
选择题
Bob promises to join in the football match _____ he has to help his parents on the farm. [ ]
A. if
B. as
C. unless
D. when
答案
答案:C
Bob promises to join in the football match _____ he has to help his parents on the farm. [ ]
A. if
B. as
C. unless
D. when
答案:C