A:用手捏易拉罐,易拉罐变瘪
B:将密封易拉罐置于深水中,易拉罐变瘪
C:让易拉罐从高处下落撞击地面,易拉罐变瘪
D:用注射器抽取密封易拉罐中空气,易拉罐变瘪
— does your mother usually go to the office?
— By bus.
句型转换。