A:studying with great care
B:to study carefully
C:to be studied without carelessne
D:taking great care of studying it
像我一样,像我一样地____,冷漠,凄清,又惆怅。《雨巷》
下列变化中,属于化学变化的是 ( )
两辆汽车在同一平直公路上同时出发,其位置x与时间t的关系如图所示。由图像可知,甲车的速度为____m/s,当t1=50s时,甲、乙两车相距____m。