I lay down my backpack in the hallway when I get home.
Notice that the transitive verb (the one you do to an object) is more regular than the intransitive verb (the one you do to yourself). Lay adds -ing and -ed (with a spelling change). Lie adds -ing, but changes to lay and lain.
I lie down on my bed when I am tired.
I am lying down on my bed right now.
I lay down on my bed yesterday.
In the past I have lain down on my bed.
I lay my backpack down in the hall.
I am laying my backpack down.
Yesterday I laid my backpack down.
In the past I have laid my back pack down.
Practice What You've Learned
Choose the correct verb to complete the sentence.
I was sure I hadlay/laidmy keys down by the front door, but somehow they got into the refrigerator.
The tigerlaid/layin wait in the bushes, waiting for a deer to pass by.
I have oftenlain/laidawake at night worrying about the next day.
Allison usuallylies/laysher rings down on the sink when she washes her hands, but sometimes she forgets them.
I knew my little brother waslying/layingin wait behind the door, waiting to jump out and scare me, but I played along.
The lawyerlay/laidher files aside and spoke passionately to the jury.
The accident victimlay/laidon the side of the road until the ambulance arrived.
Julie islying/layingout her clothes for tomorrow.
The castlelies/layson the bank of the Rhein River.
Before we moved, my catlaid/layin the bathroom window whenever it was sunny.