It's 11: 00 pm now, but the light in Peter's room is still on. He must have forgotten _______ before going to bed.
A：turn it on
B：to turn it on
C：turning it off
D：to turn it off
“青山有幸埋忠骨，白骨无铸佞臣”。对联中“忠骨”指的是谁（ ）
