4.8÷25÷4=4.8÷(25×4)=4.8÷100=0.048,这是运用了()
A:乘法结合律
B:除法结合律
C:除法的运算性质
在显微镜下观察根尖的结构,由顶端依次向上是( )
John: What do you do on Sundays?
Tom: I read books and watch TV. What do you do on Sundays?
John: I do my homework . What about you, Mary?
Mary: I clean my room and watch TV.
John: You're helpful.