Go for it now. The future is promised to no one.
Without hard work, nothing grows but weeds.
It's always too early to quit.
Only the educated are free.
To know oneself, one should assert oneself.
The wise does at once what the fool does at last.
Either you run the day or the day runs you.
The dog that trots about finds a bone.
Problems are not stop signs, they are guidelines.
Be kind whenever possible. It is always possible.
All the mathematical sciences are founded on relations between physical laws and laws of numbers, so that the aim of exact science is to reduce the problems of nature to the determination of quantities by operations with numbers.