I'm running late for work.
事实上I'm running late for work与I'm going to be late是有很大区别的
这是wordreference论坛里Harry Batt的说法,比较有参考价值
地址是
http://forum.wordreference.com/showthread.php?t=1270553There is a clear cut difference between these expressions. "I'm running late," is the idiomatic expression used when a person wants to be excused for the likelihood that he will be late. It may also be used to cut off a conversation, eg., the listener wants to quit talking interrupts the speaker with, "I have to hang up, I'm running late." It would be bad taste for the speaker to continue talking and he would be expected to yield the phone by hanging up.
"I'm going to be late," is the notice that a person gives when he is definitely going to be late. He may explain or not explain the reason why. In the former circumstancve where he has said, "I am running late," should the speaker continue to jabber on, the listener could interrupt again with, "I'm going to be late. Sorry, I'm hanging up."
In the context of your illustration if the speaker knows that he is going to be late, he should explain that he is overloaded with work and definitely will be late.
I'm running late for work是快迟到还没迟到,还可能赶上。就像打电话时你赶着上班而那哥们还唠叨个没完,你说“我赶着上班,先挂了!”差不多
I'm going to be late是说铁定要迟到了
不过两者混用也很常见,区别貌似也可忽略