Unit12SectionB(3a—self-check)一、选择填空题()1.It__________sunnytoday,butit__________cloudyyesterday.A.is,isB.was,wasC.is,wasD.was,is()2.I___________atschoolnow,butI_________athomeanhourago.A.am,amB.was,wasC.am,wereD.am,was()3.---___________thereanystudentsintheclassroom?---No,therearen’t.Butthere_____________somehalfanhourago.A.Are,wereB.were,areC.are,areD.were,were()4.---Where__________youlastnight?---I_________athome.A.are,amB.am,am...