First, read the English article below.

Most of the usual signs of ripe fruit don't mean much on a pineapple. Sniff the base of the pineapple instead: a strong scent means the pineapple is ripe. If you can barely smell it, it's probably not. Cold pineapples never smell strong, so leave them at room temperature for a while before you try this. A yellow-skinned pineapple is a safer choice than a green one, but this isn't a perfect test. Some pineapples are ripe when completely green. Others have golden or red skins, but are still hard and unpleasant to eat. Pineapples do not ripen properly after they are picked. On your kitchen counter, the pineapple will become softer and juicier, but it will not become sweet. All of a pineapple's sugar comes from the starches in the stem of the plant. Once that source is cut off, the pineapple cannot make more sugar on its own.  Green pineapples will usually change color as well. It's possible that the pineapple will become even more acidic if stored too long. If the pineapple does have a little starch left to convert to sugar, this will be in the base of the fruit. In theory, the sugar might spread better if you keep the pineapple upside down. In practice, the effect is hard to notice, but it might be worth a try.  The skin color also travels from the base upward, although this isn't relevant to the ripeness after picking. If it's difficult to prop up your pineapple, twist off the top and place the exposed end on a damp paper towel. The pineapple should soften within a day or two. Most pineapples will quickly ferment if stored for much longer than this.  If the pineapple was picked unripe, it will still be unpleasant to eat. Keep reading to find out how to improve the taste of an unripe pineapple. If you're not ready to eat the pineapple yet, move it to the fridge for another 2–4 days. 

Now, please write a short abstract for it in Vietnamese. Abstract:
Ngửi quả dứa để kiểm tra độ chín. Lưu ý rằng quả dứa sẽ mềm hơn nhưng không ngọt thêm. Lật ngược quả dứa (không bắt buộc). Để dứa ở nhiệt độ phòng.