Enough is one of those words that can be used as an adjective and an adverb. The adverb enough is used to modify an adjective. In this case, it goes after the adjective it modifies.
- She is old enough to earn a living. (NOT She is enough old to earn a living. Here the adverb enough modifies the adjective old.)
- Is it warm enough for you? (NOT Is it enough warm for you?)
- He was kind enough to lend me a few dollars. (NOT He was enough kind to lend me a few dollars.)
- These shoes are not big enough for me.
Enough is often followed by an infinitive structure.
- She is old enough to live on her own.
- She didn’t work hard enough to pass the test.
- We aren’t rich enough to buy a car.
- Some tablet computers are small enough to fit inside your pocket.
- The mangoes aren’t ripe enough to eat.
- She didn’t run fast enough to win.
The infinitive structure can be preceded by for + noun / pronoun.
- It is late enough for the kids to go to bed.
- There was not enough light for us to see what was happening.
When enough is used as an adjective, it modifies a noun. The adjective enough goes before the noun it modifies.
- I have bought enough eggs. (NOT I have bought eggs enough. Here the adjective enough modifies the noun eggs.)
- I didn’t get enough time to write the test. (NOT I didn’t get time enough to write the test.)