Why is the telephone convenient?
1. We don't have to talk face to face.
2. We don't have to write letters to someone that is far away from us.
3. We don't have to write letters to people who are far away from us.
4. We don't have to visit others' houses to talk with them.
5. We don't have to spend a lot of money riding a bus, a car or a taxi.
6. We don't have to go to a place that is far away from us to talk with others.
7. We don't have to go to a market to buy food. We can call the shopkeeper, and then we can get food delivered.
(Are the answers all grammatical and good?)
All are fine. #3 is better than #2, though, because when referring to people, "who" is better than "that."
The answers you provided are understandable, but there are a few improvements that can be made to enhance clarity and grammar. Here are revised versions of your statements:
1. A telephone allows us to communicate without being physically present with the other person.
2. By using a telephone, we can avoid the need to write letters when we want to reach someone who is far away.
3. Similarly, a telephone eliminates the need for written correspondence for long-distance communication.
4. The convenience of a telephone means we don't have to visit others' houses to have a conversation.
5. A telephone saves us money on transportation expenses like bus fares, car fuel, or taxi fares.
6. With a telephone, we can communicate with people from a distance without the need to travel.
7. Additionally, a telephone allows us to order food from a shop without needing to physically visit the market. This enables us to have food conveniently delivered to our location.
These revised statements are grammatically correct and provide a clearer explanation of why telephones are convenient.