"Memorize   these words." "Learn this spelling rule." "Don't forget about the exam tomorrow." You remember things every day, but how do you do it? When you want to call a store or an office that you don't call often, you look in the telephone book for the number. You _ the number, and then you forget it! You use your short-term   memory to remember the number. Your short-term memory lasts about half a minute. However, you don't need to look in the telephone book for your best friend's number because you already know it. This information is in your long-term memory. Your long-term memory has everything that you remember through the years. The major reason for forgetting something is because you do not learn it well at the beginning. For example, you meet some new people, and right away you forget their names. You hear the names but you do not learn them, so you forget them. According to the passage, people forget things mainly because   _  .
they are too lazy to remember them they don't have a long-term memory they only have a short-term memory they don't learn them well at the beginning