There are several ways you can find out about the countries and places you wish to visit. You can talk to friends who have travelled to the places. Or you can go and see a colour film. Or you can read travel books.
It would seem that there are three kinds of travel books. The first are those that give a personal, subjective (主观的) account of travels which the author has actually made himself, if they are informative and have a good index (索引), then they can be useful to you when you are planning your travels. The second kind are those books whose purpose is to give a purely objective (客观的)description of things to be done and seen. If a well-read, cultured person has written such a book, then it is even more useful. It can be sorted as a selected guide book. The third kind are those books which are called "a guide" to some place or other. If they are good, they will, in addition to their factual information, give an analysis or an explanation. Like the first kind they can be inspiring and interesting. But their basic purpose is to help the reader who wishes to plan in the most practical way.
Whatever kind of travel book you choose you must make sure that it does not describe everything as "wonderful", "excellent" or "magical". You must also note its date of publication because travel is a very practical affair and many things change quickly in the twenty-first century. Finally, you should make sure that the contents are well presented and easy to find.The date of the publication must be noticed because （）.

• A、the world is changing and so are the places you are going to visit
• B、the price of the book is always changing
• C、the author of the book may be different
• D、the contents of the book are always the same