题目

International Driver’s License-Vacation   For more than 50 years, travelers  61 (use) the international driver’s license to travel in foreign countries. The idea is  62 a driver with a valid driver’s license in her own country can drive freely in  63 country without going though another driving test. Of course, this is true only for countries that is  64 (involve) in this program.   The United Nations has a detailed guideline for how the license should be presented,  65 (include) what information and what languages should be displayed. It is  66 (fair) easy to get one. �复数是实系数方程的根，则            .