1. How much gas do you need?

(What does gase mean? Just gas or gasoline?)

2. I ate a piece of watermelon.
3. I ate two pieces of watermelon.
4. I ate a piece of watermelons.
5. I ate two pieces of watermelons.
(Which ones are correct?)

The word "gas" is usually short for "gasoline" -- especially when referring to cars. The word "gas" can also be referring to natural gas, a different fuel that is used mostly for cooking and heating.

2 and 3 are correct; 4 and 5 are incorrect.

They all are correct gasoline is a short word for gas so all the of the answers are correct

1. "Gas" can refer to both "gas" and "gasoline," depending on the context in which it is used. In colloquial language, "gas" is often used to refer to gasoline. However, it can also be used as a general term for any gaseous substance.

To determine whether "gas" is referring to "gasoline" or simply a gaseous substance, you would need to consider the context in which it is being used. If someone is talking about filling up their vehicle or discussing the cost of fuel, it is likely referring to gasoline. If the context is about a gas leak or the properties of gases, then it is referring to a gaseous substance in general.

2. The sentence "I ate a piece of watermelon" is grammatically correct. It indicates that you ate a single piece of watermelon.

3. The sentence "I ate two pieces of watermelon" is also grammatically correct. It indicates that you ate multiple pieces of watermelon.

4. The sentence "I ate a piece of watermelons" is not grammatically correct. You should use the singular form "watermelon" when referring to specific pieces of the fruit.

5. The sentence "I ate two pieces of watermelons" is also not grammatically correct. Like in the previous example, the correct form would be "two pieces of watermelon."

In summary, the correct sentences are:
- "I ate a piece of watermelon."
- "I ate two pieces of watermelon."