When you start a sentence with As do use comma?

You don't need a comma after "as" when you start a sentence with "As do...".

Here's why:

* "As do" is a conjunction introducing a clause that parallels a previous clause.

* Conjunctions generally don't require a comma unless there is a series of items or an introductory phrase.

Example:

* "He loves to read, as do I."

When to use a comma after "as":

* When "as" is used as a preposition: "I saw him as he walked by."

* When "as" introduces a dependent clause: "As the sun set, the sky turned orange."

Let me know if you have any other grammar questions!