A:①-降水
B:②-蒸发
C:③-水汽输送
D:④-地表径流
用井绳从井里向上提水,提水时手受到竖直向下的拉力,这个拉力的施力物体是( )
Amy spends more time writing than ________. So her writing is better than _______.
1.9˙>1.99