act of signing contracts的用法和样例：
- This dreadful murder is surely the act of a madman.
- Kupriyanov says the Gazprom decision is based on lack of progress in Russian-Ukrainian talks and the absence of signed contracts with Ukraine's Naftogaz energy company.
- Don't complain of anybody. This is an act of God.
- He was caught in the very act of espionage.
- She worked over the first act of the play.