几道关于情态动词的英语题目：1.WouldyoubesokindastokeepaneyeonmyhousewhileIamaway?(so+adj.+astodosth怎么理解,这里的Would能不能改为Can或Could,原因）2.Shouldthepainreturn,takeoneofthesepills.怎

　　几道关于情态动词的英语题目：

　　1.WouldyoubesokindastokeepaneyeonmyhousewhileIamaway?

　　(so+adj.+astodosth怎么理解,这里的Would能不能改为Can或Could,原因）

　　2.Shouldthepainreturn,takeoneofthesepills.怎么理解这个should

　　3.HeorderedthatTomshouldleavethhouseatonce.这里的should可以换成must吗?原因.

　　4.Thereisaknockatthedoor.Whocanitbe?这里的can能改成may?原因.

　　5.-Canyougoswimmingwihtusthisafternoon?

　　-Sorry,Ican't.I____takecareofmylittlesisterathomebecausemymotherisill.

　　A.canB.mayC.wouldD.haveto

　　6.-Mr.Smithmusthavebeentoyourhomethismorning.

　　-No,he______,becausehedidn'tknowmyaddress.

　　A.couldn'tB.can'tC.mustn'tD.maynot