A:did the car speed by
B:the car sped by
C:does the car speed by
D:the car speeds by
13-5=____
13-6=____
12-4=____
17-8=____
— you your homework?
—No, I haven't.
二战后,美苏两国逐渐从盟友转变为敌手,美国首先发出对苏遏制与对抗的冷战信号。“冷战”正式展开的重要标志是( )