She’s just been promoted, hence the new car.

Hence is an adverb which has the meaning ‘and that is why’; ‘that’s an explanation for’; ‘as a consequence’ or ‘for this reason’.

There are several possibilities but it is often placed at the beginning of the second clause in a sentence, and is followed by a noun or a verb.

Because it can be used in place of longer expressions, it makes sentences shorter and more succinct, and so it is useful for improving writing style.

We wanted better communication with our customers, hence the decision to be more present on social media.

With more people working from home, there are fewer cars on the road and, hence, less pollution.

Sleeping patterns depend on age, hence the reason why teenagers usually go to bed later and get up later.

Brainstorming stimulates some unexpected ideas and hence facilitates innovation.

They’re working on some cutting cutting-edge technology in their laboratories, hence all the extra security.

I didn’t have time to proofread, hence the typos!

Note that the word ‘hence’ has other meanings that are different from this one. If in doubt, check in a good dictionary.