Half a hundred miles is a hundred miles, and ninety miles is half the battle. The closer the metaphor is to success, the greater the difficulty. One thing is almost over, and you can't relax. Admonitory language. It can be used on senior three students.

source

In the Western Han Dynasty, Liu Xiang wrote "The Warring States Policy and Qin Ce V": "Poetry says,' He who travels a hundred miles is half ninety. This statement is difficult at the end of the road. It means walking a hundred miles, and walking 90 miles is half way. The closer the metaphor is to success, the more difficult it is, and the more serious it should be.

translate freely

Walk a hundred miles, and walk 90 miles is half. The closer the metaphor is to success, the more difficult it is, and the more serious it should be. Often used to encourage people to do things from beginning to end. A journey of a hundred miles, ninety miles is only the beginning of half. Encourage people to do things in one go, don't give up halfway.