Our noses can smell about 10,000 different smells(气味). Some of them are very pleasant. Most of us enjoy the delicious smell of bread, especially after it comes out of the oven(烤箱). We also like the smell of grass and the air outside after it rains. The smell of cooking is often wonderful. Don't you love the smell of popcorn? Everyone has favorite smells. You may like the sweet smell of perfume(香水). But your friend might like the fresh smell of lemons.
People like good smells, but they don't like bad smells. They try to get away from them. Garbage(垃圾)can be stinky, especially when it's old. Many people don't like the chemical(化学的)smell from cleaning supplies. It gives some people headaches(头痛). Fish has a strong smell. Many people don't like it. But sometimes bad smells can surprise you. Stinky tofu and durian(榴莲)may smell terrible, but they taste really good.
Here "they" refers to(指代)____.