who is ( ) duty today?

who is on duty who is ( ) duty today? who is on duty today Who is ___ duty today? Who is on duty today?为什么用on duty Who is on duty today ?是什么意思 谢谢 [what who whose]is on duty? 找错：Who is at duty today?I am. Who is at duty today?哪儿错了/ who is on duty?什么是主语,什么是谓语,什么是宾语?who能作主语？ 填空：Who’s--------duty today Who' s ______ duty today? 2.Can you tell me ( )else is going to be on duty today?(who,whom) 2.Do you know ______ else is going to be on duty today?（who,whom） Can you tell me ( )else is goning to be on duty tody.( who whom) do you know ___else is going to be on duty today (who/whom)填空 ~~~ Do you know ____ else is going to be duty today?whom?还是who My parents are () work.Who is () duty today?括号中都要添一个介词