1. Listen to the sound: If you tap the watermelon lightly and there is a "bang bang" sound, it means the watermelon is ripe and has high sweetness. If you hear a "dang-dang" sound, it means the watermelon is not good. 2. Look at the shape: sweet and ripe watermelons are more uniform in shape, while less mature watermelons are more deformed in shape. 3. Look at the watermelon stem: Choose a watermelon with a thick and green stem. The greener the stem, the more water it absorbs, the fresher the melon is, and the watermelon is ripe and sweet.

1. Listen to the sound: Tap the watermelon lightly and if there is a "bang bang" sound, it is a ripe melon with high sweetness. If you hear a "dang-dang" sound, it means the watermelon is not good.

2. Look at the shape: sweet and ripe watermelons are more uniform in shape, while poor melons are more deformed in shape.

3. Look at the watermelon pedicle: Choose a watermelon with a thick and green pedicle. The greener the pedicle, the more water it absorbs, the fresher the melon is, and the watermelon is ripe and sweet.

4. Look at the circle at the bottom: The smaller the circle at the bottom of the watermelon, the better. A small circle means that the watermelon has a thin skin, flesh, matures quickly, and high sweetness.

5. Look at the texture: When choosing a watermelon, you should choose a melon with thick, clear texture, distinct shades, and neat texture. Such a melon will develop well and will be more delicious than a watermelon with messy texture.