Passage Two
[29]Memory, I think, is almost as important as air, water or sunshine to us. Without it, life cannot go on. We wouldn't be able to do anything since completing any task, however simple it might be, requires us to remember certain procedures, nor would we be able to communicate with people as we wouldn't be able to remember the words to express our ideas or feelings.
For us students, I think memory is particularly important. If we lose the faculty of remembering, we won't be able to learn anything since learning unavoidably involves the use of memory. And if we cannot remember the knowledge we have acquired, what's the point of learning it in the first place?
Although everyone is born with the capacity to remember things, some of us have better memories than others. [30]There are people who are said to have a photographic memory and can remember anything they have seen only once. However, [29]those of us who have a poor memory needn't panic, for there are ways to improve our memories. Paying attention, associating facts with images, visualizing images, and relaxing are some of the ways that I find especially effective. [31]But the greatest secret to keep our memory sharp is to use it as frequently as possible.

答案解析：
29. What's the speaker mainly talking about?
[D]解析：短文开头就说，记忆力几乎和空气、水、阳光一样重要。可知主题和memory有关。最后又提到，有很多种方法可以提高记忆力。所以D正确。
30. What can people with a photographic memory do?
[A]解析：短文提到“据说有照相记忆功能的人”之后说他们能够“记住任何他们只见过一次的东西”，A与后半句同义，所以正确。
31. What does the speaker recommend strongly in the end?
[D]解析：短文说，保持好记忆力的秘诀就是尽量多记。所以D正确。