Before you leave the lab,the doors and windows _shut in case of rain.A.is B.are C.is to be D.are to be选哪个,为什么选哪个

Before You Leave 歌词 ---------(close)the windows before you leave the classrom. Before you leave the classroom,please r____to close the windows. ------the windows before you leave the classroom.(please),谢了 Be ----to close the windows before you leave. You must leave the castle before 12:00怎么读 table/leave/before/food/you/ your/finish/the 排序 Remember ______(shut) all the windows before you leave leave before 7 o’clock,or you will miss the train.为什么用leave?不用leaving? before you leave?turn in the paper before leaving我想问的是 如果在before 后面加个you 还是 before you leaving吗?还是before you leave Don't forget to close the door before you leave.（改为否定句）Don't forget to close the door before you leave.（改为否定句）_____________ to colse the door before you leave. Don't forget to close the window before you leave,Mary改为同义句）___ ___close the window before you leave,Mary All the computers must be ____ down before you leave.All the computers must be ____ down before you leave.A shutB closedC takenD turned 英语翻译please ___________ all the windows and doors_____________________ before you leave the classroom.用这种格式 dont forget to close the door before you leave the room（改为同意句） Turn off the light before you leave the classroom.(用分词结构替换) 翻译Please make sure that all the lights are turned off before you leave the classroom. Be s＿ to close the windows before you leave the classroom