He sees her often but doesn't want to get too involved.
他常与她来往,但不愿用情太深。
It is good to learn at another man's cost.
前车之覆,后车之鉴。
I'm not sure. I ought to do some studying, as I've got masses of work to do, but I think I'll be too tired. Maybe I'll just watch the news on television and go to bed early.