a matter of habit的用法和样例：
- Frequency of bathing today is partly a matter of habit.
- As a matter of fact, I've never been there before.
- The entire purpose of the thirteen principles of this philosophy is to enable one to take these four steps as a matter of habit.
- It is a matter of life and death for them.
- It may be a matter of months before it's ready.
- The revolt was suppressed in a matter of hours.