Restore means to put something back to a previous state. For example, we can restore a computer when it goes wrong. We can restore law and order to a bad area of town, or we can restore old furniture etc. Replenish means to fill something up again. For example, we replenish stock in a shop when it runs out, we replenish our energy by going to sleep.

restore : "The king was restored to his throne." - The king was dethroned but then restored to his position. Replenish: "The harvest was very good this year, we were able to replenish our store of grain." = The grain had decreased but after a good season of growing grain, the amount of grain increased back up to a higher level.

The best way I can explain is that: -Restore means to fix something to it's original state. While -Replenish means to fill or add to something back to full capacity. Example: I restored my old car. (I fixed my old car to look and work like brand new.) I replenished my energy. (I rested and filled my energy level back up to full.)