의미가 다른 것은?
1. please accept our thanks for your e-mail informing that you are in demand for our new products.
2. we have received with thanks for your e-mail which you wish to buy our new products.
3. we would appreciate your e-mail informing that you are in demand for our new products.
4. we acknowledge the receipt of your e-mail which you wish to buy our new products.

답은 3번인데.. would의 차이라는데..
여기서 would가 어떻길래 그럴까요 ㅠㅠ
그리고 would와 used to의 차이가
~하곤했다에서 불규칙 규칙 그 차이 뿐인가요?