用动词ing形式改写下列句子
1.Afterthestudentshadcleanedtheclassroom,thestudentswenttotheplaygroundtowatchthefootballmatch.
2.Ourtownhasdozensoffactories,whichincludesseveralsawmills.
3.Sheiswritingalettertoafriendofhers,forshewantstoinviteshimtoattendthemeeting.
4.Afterthecityhadbeenfloodedforseveralweeks,thecityneededfood.
5.Thesecretaryworkedlateintothenight,shepreparedalongspeechforthepresident.
6.Ifellill,whichworriedmyparents.