Article in English: Fill a bucket or tub with the water you want to dechlorinate.  Do not cover it, and place it in an area with limited airborne particles and debris to prevent contamination.  Over time, the chlorine in the water will dissipate due to exposure to the sun and air.  The precise length of time needed to dechlorinate water using this method depends on the volume of chlorine you’re attempting to remove and the amount of direct sunlight the water receives. Also, the wider and shallower the container, the faster the process will occur. Check the water regularly using a chlorine test kit to determine how much chlorine remains in the water. Evaporation won’t remove chloramine, which is used instead of chlorine in some water supplies. It’s also not recommended for drinking water since contamination can easily occur. Powdered ascorbic acid (also known as vitamin C) neutralizes chlorine.  Just sprinkle the ascorbic acid over the water and mix it in.  This method works best for dechlorinating water meant for plants or hydroponics systems.  Ascorbic acid is affordable and can be obtained from most pet stores. Ascorbic acid removes both chlorine and chloramine. It also shouldn't noticeably affect the flavor of the water, if you choose to use this method for drinking water. Place the water you wish to dechlorinate as close as possible to a UV light source.  The precise amount of UV light you’ll need to dechlorinate your water depends on how much water you’re trying to dechlorinate, the strength of the light you’re using, and the presence of organic chemicals in the water.  Typically, you should treat chlorinated water using a UV light at the 254 nanometer wavelength that has a radiant energy density of 600 milliliters (20.3  fl oz) per 1 square centimetre (0.16 sq in). UV light will remove chloramine as well as chlorine. This is also a suitable dechlorination process for drinking water.

Summary in Chinese:
让氯自然蒸发。 每3.8升的水加5毫升的抗坏血酸。 使用紫外线为水脱氯。