TheopportunitytoexploreandplayandtheencouragementtodosoCan________theperformanceofmanychildren．
Heaskedmewhethermybrother________(fly)toBeijing.
Wewerebusy________(get)thingsreadyforthetrialproductionwhenhephonedus.
設二階可導函數，則（）
Weregretto________thatitmaynotbepossibletodealwitheveryrequest.
