Add punctuation: trojita Fast Qt IMAP email client 40 days in preparation
A: trojita: Fast Qt IMAP e-mail client., 40 days in preparation.

Add punctuation: Some offer views out over Princes Street to the Firth of Forth and all located only a few minutes walk from Edinburgh Castle and Waverly train station
A: Some offer views out over Princes Street to the Firth of Forth and all located only a few minutes' walk from Edinburgh Castle and Waverly train station.

Add punctuation: By adding these two costs together we can derive the total cost
A:
By adding these two costs together, we can derive the total cost.