8-25. straight.

[X is straight.] = You think like this about the shape of X: Someone can hold one end of a string in a place, and you can pull the other end of the string far from this place. When you cannot move this end of the string to be more far from the other end, then the shape of the string is like the shape of X.

[One piece of metal is long and straight, but the other piece looks like part of a circle.]

8-26. sun.

[X is the sun.] = X is something very big that is very far from all people. At different times, people in different places can see X far above them. X contains very much gas that is burning at all times. When the people in a place can see X for some time, this causes there to be much light in this place. At other times, the people in this place cannot see X for some time, and most people in this place sleep at these times.

[This place becomes cold when you cannot see the sun.]

8-27. day, days.

[X is one day.] = X is one time like this: There is part of this time when most people in this place are sleeping, because they cannot see the sun and there is not much light. After this, there is another part of this time when most people are not sleeping, because the sun is above this place and there is much light. After this, there is another part of this time when most people are sleeping, because they cannot see the sun and there is not much light.

[I worked five days, and then I did not work two days.]

8-28. sky, skies.

[X is the sky.] = X is the very big place you can see that is far above where people live. If you are not inside a building and not below other things, you can look up through the air and see X.

[When I look up, I see the sun and the sky.]

You can see the sun above this tree and building.

Each day, __________.

• the sky is inside this building
• the sun is inside this building
• you can look at the sky and see the sun here