下列物态变化的现象中,属于熔化现象的是( )
A:初春,冰雪消融
B:夏天,湿衣服晾干
C:深秋,清晨草叶上的霜
D:冬天,自来水管冻裂
如图,已知AB∥CD∥EF,AD:AF=3:5,BE=10,那么BC的长等于____ .
—First I did my homework, and then I played piano for half hour.
下列实验操作中,正确的是( )