The missing boys were last seen ________ near the river.
A
所填的词为主语补足语，因其后有明确的地点，补足语表示动作当时正在进行中，所以只能使用playing。
Whycouldn’tyou________ananswerwhenIaskedyouwhyyouwerelate?
Thefirsttaskofabrochureisto_______.
WhichofthefollowingcountryisnotamemberofOECD?
Shewas________beunabletospeak
Asforfamilyeducation,parentsareencouragedtorelyon________ratherthanpunishment.
