单选题 I don't know about him, ______comment on him behind his back.
【正确答案】 A
【答案解析】解析：我不认识他，更不用说背后对他加以评价了。Let alone更不用说；let(sth.)go松开，放手，不理会，不再考虑；leave alone不打扰。故选择A。