Everyone is here______Lei,he is ill in hospital. []

English is___ useful language because people in many countries are using it.

I hope we only have half an hour ____ homework, so we can have more time ___ our hobbies.

He knows that thing __________ sure.[ ]

Couldyouaskhimifhe_______tomybirthdaypartynextSunday?—Iwill,ifI_______himthisafternoon.[ ]