例：Success is difficult, it requires hard work and tenacity.
Success is difficult because it requires hard work and tenacity.
For many reasons,success is difficult.
Because it requires both hard work and tenacity,success is difficult.
The reason success is difficult is that it requires both hard work and tenacity.
Use your experience and your persistence and you will succeed.
Generally speaking,success requires hard work.
Confident and resourceful,a successful person must possess these two key traits.
Requiring a person to have both hard work and tenacity,success is difficult.
To be an successful person,one must be able to accept failure.
Not only hard work but also tenacity is required to be a successful person.