Who clean the blackboard yesterday?

Who clean the blackboard yesterday? cleaned,who,blackboard,yesterday,the 排列 --Who ___to clean the blackboard __class?--The students of T 填空：who is s____ to clean the blackboard? who's on d___ today please clean the blackboard clean the blackboard TEACHER-who cleaned the blackboard yesterday?JOHN-I did. clean the blackboard的意思 Let me clean the blackboard clean blackboard 和clean blackboard区别,为什么要加the, 原因 为什么用would like who would like to clean the blackboard ()turn is it to clean the blackboard today?a:who.b:which,c:w