the back cover 什么意思

the back cover 什么意思 Back cover open ciose the Back cover 复印机故障显示 back cover open close the back cover 出现back cover open close the back cover. 兄弟出现back cover open close the back cover. cover page什么意思? 吉他cover什么意思 cover什么意思? 我的联想3220一体机提示Back cover open close the back cover.如题 打印机上的 back cover open close the back cover 是什么意思呀 兄弟7010开机滴滴的响、出现Back cover open close the Back cover是怎么回事? 联想打印机,M3120 ,出现close the back cover,back cover open!