=>
1. Stamp collection is an interesting hobby.
-> a/an + N số ít (an đứng trước nguyên âm)
2. You can learn many things, such as the geography of a country from stamps.
-> can V : có thể làm gì
3. Postal stamps are a source of interesting facts and important dates about every country in the world.
-> a source of ~ một nguồn...
4. It makes stamp collecting become very popular.
-> make sth V : khiến/làm cho
5. As you look at the pages of a stamp album, you can learn interesting details of foreign customs, arts, literature, history, and culture.
-> can V : có thể làm gì
6. Their colors can make you feel relaxed and hapy.
-> make sb V : khiến/làm cho
7. Collecting stamps can become a business.
-> can V : có thể làm gì
8. If you are lucky in finding a special stamp, it will bring you some money besides knowledge and pleasure.
-> câu đk loại 1: If S Vs/es, S will V