9-08. month, months.
[X is a month.] = X is a time that contains four groups of seven days. Some of these times contain one or two or three days more.
[Most people live nine months inside the body of their female parent.]
9-09. year, years.
[X is a year.] = X is a long time that contains four groups of three months.
[There are not many people who live more than one hundred years.]
9-10. fly, flies, to fly, flying, flew, flown.
[X is flying.] = X is something solid moving through the air for a long time. X is touching the air, but not touching other things.
[Some kinds of animals can fly.]
[People make some machines that can fly.]
9-11. bird, birds.
[X is a bird.] = X is a kind of animal that has two legs. This kind of animal does not have hair, but many long flat things grow out of the surface of its body and cover most parts of its body. There are many kinds of animals like this. Most can fly when they move the long flat things that cover the sides of their bodies.
[A bird is on top of the building after it flew up from the ground.]