Add punctuation: Some sites offer online blackjack software with topofthenotch 3D graphics that allow you to choose a 3D character walk around a 3D casino or blackjack room and chat with other players and play at a 3D blackjack table against a 3D blackjack dealer
A: Some sites offer online blackjack software with top-of-the-notch 3D graphics that allow you to choose a 3D character, walk around a 3D casino or blackjack room and chat with other players and play at a 3D blackjack table against a 3D blackjack dealer.

Add punctuation: His favourite course during his first year had been calculus and its applications so since he had always enjoyed mathematics there was an obvious direction in which to take his studies
A: His favourite course during his first year had been calculus and its applications so, since he had always enjoyed mathematics, there was an obvious direction in which to take his studies.

Add punctuation: If ovulation is normal there are other fertility tests available
A:
If ovulation is normal, there are other fertility tests available.