0. I am old enough to understand this situation 

1. I am not tall enough to reach the ceiling

2. She is sociable enough to make friends easily

S+be+adj+enough+(for Sb)+to_V

3.  He is looking at himself in the mirror.

S+be+V_ing+...

4. I have to stop smoking

S+ have to + Vbare

0. I/ old / enough / understand / situation.

-> I am old enough to understand the situation. 

1. I / not tall / enough/ reach / ceiling

 I'm not tall enough to reach the ceiling.

2. She / sociable / enough / make friends easily

-> She is sociable enough to make friends easily. 

3. he/looking/ is/ at/himself/ mirror/in/the

->He is looking at himself in the mirror.

4. I/have/to smoking/stop

->I have to stop smoking.

 Enough to: đủ….để có thể làm gì

Công thức: 

S + V + adv + enough + (for somebody) + to + V

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

Have to dùng để diễn tả một nghĩa vụ mạnh mẽ

Subject + have to + V