He spent all day at his desk.为什么不是on the desk

He spent all day at his desk.为什么不是on the desk he sit ( )his desk all day ( )his head( )his hands.he is kee the student is sitting at his desk 为什么用at? He ( ) the clock together and put it on his desk. he put his head on the desk and said 1.He __________ his watch on the desk yesterday. _____are on the desk.A.His books all B.All his books C.His a he spent a whole night () the desk for the math exam.A.on,B. at the desk和on the desk区别是什么 语法填空 the other day john sat什么his desk and all of a sudden th he said he ---(leave) a message on the desk the next day "He hurried to his home,with his book __ on the desk".(A.to