Situation: Describing a problem with a car.
Formal:
* The automobile is experiencing a malfunction in its braking system.
* An unacceptable level of noise emanates from the engine compartment.
* The vehicle requires immediate attention from a qualified mechanic.
* The tire pressure is significantly below the recommended level.
* A comprehensive diagnostic assessment is necessary to determine the extent of the damage.
Informal:
* My car's brakes are messed up.
* The engine's making a really weird noise.
* I need to get my car fixed ASAP.
* My tires are flat.
* Something's seriously wrong with my car; I need to take it to a shop.
Situation: Expressing gratitude.
Formal:
* I would like to express my sincere gratitude for your assistance.
* We are deeply indebted to you for your generous contribution.
* Your thoughtful gift is greatly appreciated.
* Please accept my heartfelt thanks for your support.
Informal:
* Thanks a bunch!
* I really appreciate your help.
* Thanks for the gift!
* I owe you one!
Situation: Making a request.
Formal:
* I would be grateful if you could submit the report by the end of the week.
* Your prompt attention to this matter would be greatly appreciated.
* Kindly provide the necessary documentation at your earliest convenience.
Informal:
* Can you send me the report by Friday?
* Please get on this ASAP.
* Send me the paperwork when you can.
The differences lie in word choice (e.g., "automobile" vs. "car," "assistance" vs. "help"), sentence structure (more complex sentences in formal writing), and tone (formal language is more serious and less conversational). Formal language avoids contractions and slang, while informal language often uses them freely.