act of fact的用法和样例：
- As a matter of fact, I've never been there before.
- This dreadful murder is surely the act of a madman.
- As a matter of fact, light is a form of energy.
- Don't complain of anybody. This is an act of God.
- He was caught in the very act of espionage.
- As a matter of fact, I didn't know him at all.