Entrance stairs or step(入口楼梯或台阶) operate in conjunction(一起,共同) with but are not integral part of entrance doors. (但并不是入口门的组成部分。)( )
A.Entrance stairs or step are connected with entrance doors and move accordingly. B.Entrance stairs or step are integrated with entrance doors and operate together. C.Although entrance stairs or step operate together with entrance doors, they are not integrated.正确答案C
