Affect and effect are two of the most commonly confused words in English, but don't worry—we'll help you keep them straight. The basic difference is this: affect is usually a verb, and effect is usually a noun.

Can effect or can affect?

Affect is a verb – “to affect” – meaning to influence or have an impact on something. Effect is the noun – “an effect (a positive or a negative effect) is the result of being affected by something.

Did the cold affect or effect you?

The verb affect means “to act on; produce an effect or change in” as in The cold weather affected the crops (it produced a change in the crops … probably killing them). ... So, when you're looking to use one of these two terms to express an action, chances are you're looking for affect.