Takeaway: Sending a less-than-perfect e-mail to a friend is one thing; mistakes aren't really a problem. But if you want to craft an error-free message that reflects your professionalism, be on the lookout for these common grammatical slip-ups.

These days, we tend to communicate via the keyboard as much as we do verbally. Often, we're in a hurry, quickly dashing off e-mails with typos, grammatical shortcuts (I'm being kind here), and that breezy, e.e. cummings, no-caps look. It's expected. It's no big deal. But other times, we try to invest a little care, avoiding mistakes so that there's no confusion about what we're saying and so that we look professional and reasonably bright.

In general, we can slip up in a verbal conversation and get away with it. A colleague may be thinking, Did she just say "irregardless"?, but the words flow on, and our worst transgressions are carried away and with luck, forgotten.

That's not the case with written communications. When we commit a grammatical crime in e-mails, discussion posts, reports, memos, and other professional documents, there's no going back. We've just officially gone on record as being careless or clueless. And here's the worst thing. It's not necessary to be an editor or a language whiz or a spelling bee triathlete to spot such mistakes. They have a way of doing a little wiggle dance on the screen and then reaching out to grab the reader by the throat.

So here we are in the era of Word's red-underline "wrong spelling, dumb ass" feature and Outlook's Always Check Spelling Before Sending option, and still the mistakes proliferate. Catching typos is easy (although not everyone does it). It's the other stuff -- correctly spelled but incorrectly wielded -- that sneaks through and makes us look stupid. Here's a quick review of some of the big ones.

#1: Loose for lose

Yes: I always lose the product key.

#2: It's for its (or god forbid, its')

Yes: Download the HTA, along with its readme file.

No: The laptop is overheating and its making that funny noise again.

Yes: The laptop is overheating and it's making that funny noise again.

#3: They're for their for there

Yes: The managers are in their weekly planning meeting.

No: The techs have to check there cell phones at the door, and their not happy about it.

Yes: The techs have to check their cell phones at the door, and they're not happy about it.

#4: i.e. for e.g.

Yes: Use an anti-spyware program (e.g., Ad-Aware).

Note: The term i.e. means "that is"; e.g. means "for example." And a comma follows both of them.

#5: Effect for affect

Yes: The outage shouldn't affect any users during work hours.

Yes: The outage shouldn't have any effect on users.

Yes: We will effect several changes during the downtime.

Note: Impact is not a verb. Purists, at least, beg you to use affect instead:

No: The outage shouldn't impact any users during work hours.

Yes: The outage shouldn't affect any users during work hours.

Yes: The outage should have no impact on users during work hours.

#6: You're for your

Yes: Remember to defrag your machine on a regular basis.

No: Your right about the changes.

Yes: You're right about the changes.

#7: Different than for different from

Yes: This setup is different from the one at the main office.

Yes: This setup is better than the one at the main office.

#8 Lay for lie

Yes: I got dizzy and had to lie down.

Yes: Just lay those books over there.

#9: Then for than

Yes: The accounting department had more problems than we did.

Note: Here's a sub-peeve. When a sentence construction begins with If, you don't need a then. Then is implicit, so it's superfluous and wordy:

No: If you can't get Windows to boot, then you'll need to call Ted.

Yes: If you can't get Windows to boot, you'll need to call Ted.

#10: Could of, would of for could have, would have

Yes: I could have installed that app by mistake.

No: I would of sent you a meeting notice, but you were out of town.

Yes: I would have sent you a meeting notice, but you were out of town.

Bonus peeve