If you learn from the paper, you will never know anything about it. (If you know something well, you must try it yourself to succeed.)

If you eat bitter, you will become a master.

Rome wasn't built in a day. (If you freeze to three feet, it wasn't built in a cold day. Metaphorically, it is the result of long-term brewing, accumulation and trying.) But what is worse is never trying.-theodore roosevelt

What was hopeless, if you try boldly, you will often succeed.-Shakespeare

How can you see a rainbow without experiencing storms?

Efforts may not be successful, but giving up will certainly fail.