Poetry: Ask the canal so clearly because there is flowing water at the source. (Zhu)?
Reason: It figuratively shows that only by reading more books can knowledge be inexhaustible and talents be uninterrupted. It encourages people to study hard and make continuous progress.
Example 2:
Poetry: Once you reach the top of the mountain, you will see that all the other mountains are dwarfed under the sky ... (Du Fu)
Reason: It tells people that they can only see far if they stand high, and encourages people to climb the peak bravely and keep making progress.