雅尔塔体系的实质是: [ ]
A.两种社会制度的斗争
B.美苏争霸斗争
C.美苏对世界势力范围的划分
D.雅尔塔会议精神的贯彻
答案:C
What _____ you do on your last school trip? [ ]
A. do
B. did
C. were