题目内容：

I didn't expect him to __me when I needed his help.A.turn back.B.turn off.C.turn on.D.turn his back on

优质解答

D.turn his back on sb 背对某人：当我需要他帮助时,我没有预料到他会置我不理.
如果原句没有me,A也是可以的
turn off.：关掉
turn on ：打开