you must keep your eyes ( ) when you do eye exerci

问题补充：

you must keep your eyes ( ) when you do eye exercises.A.close B.open C.closed D.opened求大神帮助如标题描述的

答案：

c 做眼保健操的时候你要把眼睛闭上.keep sth.done closed是 close 的过去分词