他今天有面试，因此穿了西装。

He has an interview today, ___hence the suit.

因此，如果他们系着安全带，他们往往在驾驶时冒更多风险。

___Hence, if they are wearing seat belts, they tend to take more risks with their driving.

因此，竞争越多，对个人和社会的好处就越多。

___Hence, the more competition there is, the more benefits are given to both people and society.