2 years old.
Cow: "Mooooove over"
Sheep: "Naaaaaaa."
or
Use a sea saw.
or
I said, "Are you two an item?"
or
1,000,001: One to change the bulb and 1,000,000 to rebuild civilization to the point where they need light bulbs again.
or
50. One to screw in the light bulb and the remaining 49 to guard him .
or
Two, one to call Daddy, and one to get the (pick one:) mineral water/Tab.
or