Paul W. Frields wrote:
It's often worth avoiding both usages here by not writing sentence fragments.TIP OF THE DAY: If you use the word "this" or "that," follow it with a noun that clearly indicates the antecedent. Ensure that your use of "this" or "that" isn't also an indicator of poor sentence construction. The word "lets" or "allows" following "this" or "that" is generally a sign that more editing is needed. INCORRECT: "This shows the user who owns the process." CORRECT: "This option shows the user who owns the process."
More correct: "Option -x shows which user owns the process"
More correct: "Test packages not pushed to the 'stable' respository by turning on the 'updates-testing' repository. "INCORRECT: "Turn on the 'updates-testing' repository in the Software Sources tool. This lets you test new packages before they are pushed to the stable repository." CORRECT: "To test new packages before they are pushed to the stable repository, turn on the 'updates-testing' repository in the Software Sources tool."
You can be far more succinct and clear by making every sentence stand alone. If a sentence does not make sense without the sentence before it, consider revision.Be on the lookout for naked "this" or "that"!
Chris