1. As the saying goes, an inch of time is worth an inch of gold, but an inch of gold cannot buy an inch of time. Time really flies by, time flies like an arrow. 2. How can you see a rainbow without experiencing wind and rain? This is true at all. Three feet of ice does not freeze in a day. 3. Genius is ninety-nine percent hard work and one percent inspiration. Edison's famous saying fully illustrates that nothing is difficult in the world but only for those who are determined. Hope it will be adopted.