Did you clean the room last night?linda are a gond girl.she get up early in the morning.she wash her face and brush her teeth.then she have her brekfast.she go to school at half past seven.now it eight thirty.linda and her classmates is have a maths lesson.mr wang is writeing aquestion on the black board.lt say how much is ten plus seven.linda's answer are seventy.she make a mistake.she feel sorry.错在哪？