【1.____(come)at4o'clockiftheplanearrivesontime.2.Ididn'tgoshoppingthismorningasI___(do)thehousework.3.She___(come)toseemeyesterday,butsheforgot.4.You___(ask)forpermissionbeforeyouleftthetable.5.Astheydidn'tunderstand,I_】

　　1.____(come)at4o'clockiftheplanearrivesontime.

　　2.Ididn'tgoshoppingthismorningasI___(do)thehousework.

　　3.She___(come)toseemeyesterday,butsheforgot.

　　4.You___(ask)forpermissionbeforeyouleftthetable.

　　5.Astheydidn'tunderstand,I___(explain)everythingagain.

　　用should,oughtto和haveto来填空!