Learning is like sailing against the current. The next sentence is that the heart is like a plain. Learning is like sailing against the current. If you don't advance, you will retreat. Heart like a plain. It means the boat is sailing against the current. If it doesn't take the initiative to move forward, it will be affected by water and go backwards. Like a horse on the grassland, if it doesn't know how to move freely, it will run away. It describes that no matter what you do, you must have your own opinion, your own judgment and know how to control yourself. Learning is like sailing against the current, if you don't advance, you will retreat, and your heart will be like a plain. This sentence comes from the grace of a wise man. Liang Qichao in the Qing Dynasty once said in the "Shanxi Ticket Merchants Welcome Meeting": "It's enough for a husband to keep his old age! However, I think that in the world, it is like sailing against the current. If you don't advance, you will retreat. "