Add punctuation: Such combinations rarely occur but when they do there are often opportunities for very profitable trades
A: Such combinations rarely occur, but when they do, there are often opportunities for very profitable trades.

Add punctuation: Our craft is business analytics and implementation always complies with our data warehouse best practice
A: Our craft is business analytics, and implementation always complies with our data warehouse best practice.

Add punctuation: What is File Extension OTF
A:
What is File Extension OTF?