1. I am too tired to focus on the teaching.

I am too tired to do the laundry.
I am too tired to mop the floor.
I am too tired to iron my uniform.
I am too tired to clean the living room.
I am too tired to arrange the things in the living room.

2. I am too young to use the website.
I am too young to get a driver¡¯s license.
I am too young to carry the heavy box.
I am too young to go to college.
I am too young to go abroad by myself.
I am too young to go on a picnic without my teacher.

3. I am too old to lift the heavy box.
I am too old to walk down the stairs alone.
I am too old to earn money.
I am too old to work at a construction site.
I am too old to drive a truck.
I am too old to travel to Japan by myself.
I am too old to join the ping-pong club.

4. I am too busy to join the trip.
I am too busy to go to academy.
I am too busy to play cricket with you.
I am too busy to go to see the movie with you.
I am too busy to go to the PC room with you.
I am too busy to organize my room.
I am too busy to chat with you on the computer.
I am too busy to send messages with/on Kakao Talk.
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I have made simple English sentences containing the too - to structure. Would you check them please? I need correct sentences. Thank you.

These are all correct! Congratulations. I assume you made a typo, but "driver's" license should have an apostrophy, not all those other marks. :)

And I just misspelled apostrophe, also a typographical error!

Sure! Here are some corrections to your sentences:

1. I am too tired to focus on teaching.
2. I am too tired to do the laundry.
3. I am too tired to mop the floor.
4. I am too tired to iron my uniform.
5. I am too tired to clean the living room.
6. I am too tired to arrange things in the living room.

2. I am too young to use the website.
2. I am too young to get a driver's license.
3. I am too young to carry a heavy box.
4. I am too young to go to college.
5. I am too young to go abroad by myself.
6. I am too young to go on a picnic without my teacher.

3. I am too old to lift a heavy box.
2. I am too old to walk down the stairs alone.
3. I am too old to earn money.
4. I am too old to work at a construction site.
5. I am too old to drive a truck.
6. I am too old to travel to Japan by myself.
7. I am too old to join the ping-pong club.

4. I am too busy to join the trip.
2. I am too busy to go to the academy.
3. I am too busy to play cricket with you.
4. I am too busy to go see a movie with you.
5. I am too busy to go to the PC room with you.
6. I am too busy to organize my room.
7. I am too busy to chat with you on the computer.
8. I am too busy to send messages on KakaoTalk.

These corrected sentences are grammatically accurate and convey the intended meaning.