выписать из текста предложения с глаголом to have и определить его функцию
If you do not use arms or for some time, they become weak, when you start them again, then slowly become strong again. Everybody knows this, and nobody would think of guestioning this fact. Yet there are many people who do not seem to know, that memory works in the same way. When someone says that he has a good memory, he really means that he keeps his memory in practice by exercising it regularly, either consciously or unconsciously. When someone else says that his memory is poor, he really means that he does not give it enough opportunity to become strong. The position is exactly the same as that two people, one of whom exercises his arms and legs by playing tennis, while the other sits in a chair or motor-car all day.
If a friend complains that his arms are weak, we know that it is his own fault. But if he tells us that he has a poor memory, many of us think that his parents are to blame, or that he is just unlucky, all of us realize that it is just his own fault. Not all of us can become extremely strong or clever, but all of us can, if we have ordinary bodies and brains, improve our strength and our memory by the same means -practice.
Have you ever noticed that people who cannot read or write usually have better memories that those who can? Of course, because those who cannot read or write have to remember things: they cannot write them down in a little notebook. They have to remember dates, times and prices, names, songs and stories, so their memory is the whole time being exercised.
So if you want a good memory learn from those who cannot read, practice remembering.

1). When someone says that he HAS a good memory, he really means that he keeps his memory in practice by exercising it regularly, either consciously or unconsciously. - выступает в роли смыслового глагола "иметь".2). But if he tells us that he HAS a poor memory, many of us think that his parents are to blame, or that he is just unlucky, all of us realize that it is just his own fault. - смысловая функция.3). Not all of us can become extremely strong or clever, but all of us can, if we HAVE ordinary bodies and brains, improve our strength and our memory by the same means -practice. - смысловая функция.4). HAVE you ever noticed that people who cannot read ... - вспомогательный глагол  Present Perfect.5). ...who cannot read or write usually HAVE better memories that those who can? - смысловая функция.6). Of course, because those who cannot read or write HAVE TO remember things: they cannot write them down in a little notebook. - форма долженствования ("приходиться").7). They HAVE TO remember dates, times and prices, names, songs and stories, so their memory is the whole time being exercised. - форма долженствования.