Prepare the Pickling Liquid: In a medium saucepan, combine the sugar, salt, white vinegar, and water. Bring the mixture to a boil over medium heat, stirring occasionally to ensure the sugar and salt are fully dissolved. Once the mixture comes to a boil, remove it from the heat and allow it to cool to room temperature.

Prepare the Vegetables: While the pickling liquid cools, rinse the mung bean sprouts thoroughly under cool water. Peel and shred the carrot, and cut the chives or green onions into small diagonal pieces.

Combine Ingredients: In a large bowl, combine the mung bean sprouts, shredded carrot, and chives or green onions. Toss the vegetables together gently to mix evenly.

Pickling Process: Once the pickling liquid has cooled, pour it over the mixed vegetables in the bowl. Ensure that all the vegetables are submerged in the liquid. You can place a small plate on top to help keep everything under the liquid if needed.

Marinate: Cover the bowl and let the mixture sit at room temperature for at least 2 hours, allowing the flavors to meld together. For a more intense flavor, refrigerate the mixture for a few hours or overnight.

Serve: Once pickled, drain the excess liquid and serve your tangy pickled mung bean sprouts with your favorite dishes! This pickle can be stored in the refrigerator for up to a week.