【单选题】How many courtries sit as "permanent members" in the UN?
【判断题】Canada plays an important role in international affairs and it is one of the five great powers which sit on the UN Security Council.
【单选题】下列关于合作的重要性不正确的是( )。(1分)
【单选题】日本血吸虫感染人体后产生的免疫力可以杀伤再进入体内的
【单选题】设H A =15.032m,H B =14.729m,h BA =( )m。