1.汗马功劳 distinctions won in battle, one's contribution in work
During the bilateral trade negotiations, he spared neither day nor night to make them a success. His contribution was indeed great and is highly appreciated.
2.悬崖勒马 pull back before it's too late
In spite of having done wrong, you can still pull back now before it is too late and work for a bright future.
3.一马当先 be the first, take the lead
When we were climbing the mountain, he took the lead and made for the summit.
4.单枪匹马 do something single-handedly
Xiao Song, the center forward, takes the ball single-handedly into the rival's court, dodges all obstacles and shoots, he always manages to score nine times out of ten.
5.老马识途 an old hand is the best guide, an old horse knows the way