D
Americans can travel almost anywhere they choose. But to protect its people, the government lists a few dangerous places where Americans cannot go. These places are unfriendly countries or countries at war. There, the traveller might not be safe. These countries are listed in a small book called a passport（护照）.
This passport is a government request for the safety of its travelling people. It is also a government’s pledge（保证） that the people will obey the rules of the host country（东道国）.
To receive a passport from the government, a traveller must prove that he is an American citizen （公民）. An American can not go overseas（外国） without a passport. Only certain close countries such as Canada and Mexico do not ask for passports.
Pasted （粘贴）inside the passport is the traveller’s picture. Children travelling with their parents are included in one parent’s book.
Thousands of people from the United States visit other countries every year. An American traveller might carry plane tickets, money, clothing and many other things. But the most important that he carries in another country is his passport.
68. A passport is not needed when an American goes to ______.
A. foreign countries   B. dangerous areas   C. Canada or Mexico   D. countries overseas
69. From the passage we can see that ______.
A. children can’t travel to foreign countries     B. Americans like to travel
C. a traveller is not safe in most countries      D. Americans like to travel to close countries
70. Why does a traveller need a passport?
A. He needs something more to carry when he travels.
B. It helps the country to protect the people. 
C. He needs to have his picture taken more often.   
D. It helps the traveller to know where he will go.