Explanation:
If the bottle contains 500ml of water and the water fills half of the bottle, then the total capacity of the bottle must be 1000ml (since half of 1000ml is 500ml).
To convert this to liters, we can divide by 1000, since there are 1000 milliliters in one liter.
1000ml / 1000 = 1 liter
Therefore, the bottle holds 1 liter of water.