Grammar is a part of every professionals' everyday life. It's important for us to be coherent, whether we're writing an email, doing a presentation or simply talking one-on-one, yet so often grammar can trip us up.

Ignoring the occasional typos and misspellings, what are the most common grammar mistakes that we make?

The difference between number and amount
A number of people, but an amount of sugar. Things you can count cannot be described as an amount. For example, "a larger number of people have fallen sick" (not a large amount of people).

The difference between less and fewer
Less is for amounts (less sugar, less milk). Fewer should always be used for things you can count (fewer people, fewer corners, fewer nails).

The difference between lay and lie
To lay is a transitive verb. You may lay a table or a hen may lay an egg. To lie in intransitive. "He lies" can stand on its own whether it means telling an untruth or lying down. The confusion comes because the past tense of to lie (down) is lay as in "he lay down and slept".

When to use may and when to use might
Might is the past tense form and may is present. May is correct when an outcome is still uncertain. For example, "I may go to the party tonight" or "he might have gone to the party yesterday".

When to use who and when to use whom
Who is the subject of a verb. Whom is the object of a verb. Reuters' style guide suggests: "substitute he or him for the who or whom and see which makes sense. But we should follow common usage and be ready to use who as the object where this sounds and looks more natural. For example, who she met at the midnight rendezvous was not yet known."

The placement of only
Only should sit nearest the thing it is describing. For example, "the cat would eat only fish and steak" not "the cat would only eat fish and steak".

All rules are there to be broken, but only if you are aware you are breaking them! Otherwise it's best to double check and make sure we're not letting these rules slip through the net.