①过滤 ②蒸发 ③溶解 ④向容量瓶转移液体.
A:①和②
B:①和③
C:③和④
D:①和④
This is the third time he ______ late this month! He has to be reminded.
观察蚯蚓、沙蚕和水蛭的图片,它们都有共同的特点,属于( )