The only limit to our realization of tomorrow will be our doubts of today.
解析:通过实践磨练自己。
I think it's important to have a positive attitude and to be optimistic.
教育的目的不是使年轻人在任何一门科学上都变得完美,而是要打开和培养他们的思维,使他们在将来学习任何科学时都能胜任。