“As … as” says that two things are equal in some way. “Not as … as” says that the first is less than the second. The adjective stays in its basic form between the two “as”.
Form
| Structure | Example |
|---|---|
| as + adjective + as | She is as tall as her brother. |
| not as / so + adjective + as | It isn't as expensive as that. |
| as much / many + noun + as | I have as many books as you. |
When to use it
- Equality: He is as clever as his sister.
- Inequality: This test wasn't as difficult as the last one.
- With adverbs: Come as soon as possible.
- Multiples: twice as long as, half as much as.
Examples
- My room is as big as yours.
- He is not as old as he looks.
- Run as fast as you can.
- She earns as much as I do.
- It was twice as expensive as last year.
- This isn't as good as the first one.
Common mistakes
- A comparative form: as taller as → as tall as.
- Using “than” instead of the second “as”: as big than → as big as.
- Using “like” instead of “as … as”: He is like tall as me → as tall as me.