Grammar (7): Lay, lie, laid, lied

How to use the verbs lay, lie, laid, and lied
 
The first lesson to learn about the verbs lay and lie is that lay is a transitive verb and lie is an intransitive verb. A transitive verb must take an object, meaning the verb must be performed by an actor upon some other noun:
Lay down your book.
When are you going to lay that issue to rest?
As I lay myself down to sleep.
An intransitive verb does not take an object, meaning the subject just performs the verb without acting upon any other noun:
The book is lying on the table.
I’m lying in my bed.
As I lie down to sleep.
In the third example of each verb above, the presence or absence of an object (myself, my body, me) determines what verb can be used, even though they mean basically the same thing. If you said, “I’m laying on my bed,” someone might properly ask, “Laying what on your bed?”
The only reason any of this gets difficult is because English is stupid and the past tense of lie is lay. Well, the past tense of (to tell a) lie is lied, but the past tense of lie (down on something) is lay (down on something).
Last night as I lay in my bed
As soon as the dog lay down on the floor
The treasure lay undiscovered for centuries.
The past tense of lay is laid, so that shouldn’t be hard for anyone to figure out how to use.
Note, finally, the past participle of lie is lain:
Having lain down to sleep
After the dog had lain down on the floor
The treasure has lain undisturbed for centuries.
In summary, yes, you’d be right to label English as a stupid, overly difficult language for making lay the past tense of lie and to complain about this not becoming regularized (i.e., the past tense of lie always being lied regardless of meaning) sometime soon.

source: ( http://www.jpetrie.net/grammar/#lay-lie-laid), 31/03/14