1:he 是主语 tell是谓语 me和 the reason for his being late.都是宾语（tell可以加双宾语）
for是一个介词,在这里表示原因 用来修饰 reason的
the reason for his being late.是一个整体,相当于一个名词
for后面只不过是一个修饰成分
The teacher was angry at Mary being late for class.
was angry at是个词组 表示对……感到生气
但是觉得这里有点问题……Mary's being late for class.觉得这样好点……
如果知道了正确答案,麻烦追加一下,告诉我声……谢谢