how long do you often spend ------(play) football after school

问题描述:

how long do you often spend ------(play) football after school

放学后花多少时间踢足球。

playing.
词组:
1spend time (in) doing sth in通常被省
2spend time on sth

playing
spend +ing

(in) playing

playing
根据词组 spend some time in doing sth.其中的介词IN可以省略的

playing. 词组:sb. spend time (in) doing sth.