The doctor told Jimmy's mother that room must ____warm a.kept b.be kept c.to be kept
问题描述：
The doctor told Jimmy's mother that room must ____warm a.kept b.be kept c.to be kept
d.to kept
答
be kept
这题选B
因为房间必须是“被保持温暖”
所以要用被动语态：be done也就是这里的be kept