问题补充:
— will your father be back?
—My father will be back in half an hour.
A. How long
B. How soon
C. How often
D. How far
答案:
A. How long
(答案→)B. How soon
C. How often
D. How far
解析:根据题干中的will和答语,可知,应该用how soon“多久”,因为how soon用于将来时中;how long表示“多长时间”,不能用于将来时;how often是“多久一次”,是问频率;how far“多远”是问路程。所以本题选B。