First, read the English article below.

Mold or dark-colored spots on the outside of the watermelon could indicate that it has gone bad.  The mold might be black, white, or green, and have a fuzzy appearance. The watermelon should have either a consistent pine green shade or a striped appearance.  Striped watermelons have alternating lime-green and darker pine-colored stripes. These colors indicate the watermelon is healthy.  If your watermelon is a different color (black, for instance), do not eat it. Different varieties of watermelon have different internal appearances.  Desert King, Tendergold, Yellow Baby, and Yellow Doll watermelons have yellow or orange flesh. When watermelon is no longer good, the crisp flesh will start to shrivel.  The flesh might even be pulling away from the seeds.  In other cases, the watermelon might become slimy and mushy. A healthy, edible watermelon should smell sweet and fresh.  If it smells tangy or sour, it’s gone bad and should be thrown it away. 

Now, please write a short abstract for it in Chinese. Abstract:
检查表皮是否发霉。 观察西瓜表皮的颜色是否健康。 观察瓜瓤是否呈深粉色或红色。 注意西瓜是否出现果肉失水，吃起来沙沙的，有点干。 切开西瓜之前闻闻气味。