Here are a couple of tricky verbs that I came across. Both are very similar and are easily confused. Lie and lay. I found out that one is an intransitive verb (lie) and the other is transitive (lay).
Here's an example:
I lay on the beach for two hours yesterday.
It's a common mistake to say "I laid on the beach." Laid is the past tense form of the transitive verb lay, which means to beat or strike down with force. Using the word lay is the past tense form of lie. Lie in this context means to be or to stay at rest in a horizontal position.
Make sense? I had a little bit difficulty in understanding myself.