中国大学MOOC: The boys were seen _____________ football on the playground.
举一反三
- The boys were seen _____________ football on the playground. A: play B: to playing C: to play D: played
- 中国大学MOOC: The missing boy was last seen in the playground.
- Look! The boys ___________ football on the playground. A: plays B: play C: are playing D: played
- The police were told that some boys were seen ___ on the street.
- He ______ playing football by his mother on the playground. A: see B: saw C: was seen