1.IF YOU SPEAK A LOT,YOU WILL--SPEAK ENGLISH WELL.A.can B.BE

1.IF YOU SPEAK A LOT,YOU WILL__SPEAK ENGLISH WELL.A.can B.BE ABLE TO C.ARE ABLE TO D.COULD
2.Oh,my god!i lost my key ___ the door.at of to about
3.Look at your dirty trouser.You'd better___them right now.washed washing wash to wash
4.Mary decided ___hard from then on.
顺便告诉我什么为什么填这一项
第四题选择是：A.to study B.study Cstudying D.studied