5．A.boy B．teacher

　　C．girl D．advisor

　　解析：与下文的"the boy who came with him"呼应可知，来了两个男孩儿。

　　答案：A

　　6．A.written B．lost

　　C．received D．selected

　　解析：与上文的"One Monday evening，I received a direct message from a boy who found a mean message in his locker"可推知，男孩儿又收到(received)了一个便条。

　　答案：C

　　7．A.invitation B．wish

　　C．greeting D．apology

　　解析：根据下文的"I just ____31____ to do something to make up for my ____3____"可推知，对方写了一个便条以表达他真诚的道歉。

　　答案：D

　　8．A.replied B．added

　　C．shouted D．argued

　　解析：根据"It was me"可知，犯错的男孩儿回答了作者的问题。

　　答案：A

　　9．A.so B．for

　　C．or D．but

　　解析：根据语境可知，上下句表示逻辑上的转折关系。

　　答案：D

　　10．A.simple B．kind

　　C．specific D．cautious

　　解析：根据上文的"I know it was wrong and not at all kind"可知，犯错的男孩儿希望用友好的语言来得到原谅。

　　答案：B

　　11．A.wanted B．continued

　　C．failed D．refused

　　解析：根据语境可知，犯错的男孩儿想(wanted)做些事情去弥补自己的错误。

　　答案：A

　　12．A.carelessness B．loneliness

　　C．meanness D．sadness

　　解析：与上文的"a mean message"呼应可知，C项正确。

　　答案：C

　　13．A.special B．unique

　　C．wise D．brave

解析：与下文的"I told him how courageous it was for him"呼应可知，作者认为承认错误的这个男孩儿很勇敢。