题干
He _____ football regularly for many years when he was young.
A：was playing
B：has played
C：played
D：had played
答案(点此获取答案解析）
C
He _____ football regularly for many years when he was young.
A：was playing
B：has played
C：played
D：had played
随时间t变化的图象分别如图①～④所示，下列说法正确的是