Công thức:
(by + reflexive pronoun = alone, without any help, with no help)
REFLEXIVE PRONOUNS (Đại từ phản thân)
I - myself
You - yourself
He - himself
She - herself
It - itself
We - ourselves
You - yourselves
They - themselves

S + be + adj + enough + (for somebody) + to V

1. No one helped me repair my bike. 
=>I repaired my bike by myself.
2. No one helps Lan type this document. 
=>Lan types this document by herself.
3. No one helped my Dad wash his car.
=>My Dad washed his car by himself.
4. No one helps the little boys carry their bags. 
=>The little boys carry their bags by themselves.
5. Peter is hard-working. He will pass the exam easily. 
=>Peter is hard-working enough to pass the exam easily.
6. The film is very interesting. I can watch it many times. 
=>The film is interesting enough for me to watch many times.