A：目镜10×，物镜10×
B：目镜10×，物镜20×
C：目镜10×、物镜40×
D：目镜5×、物镜10×
____－2＝6、____－2＝5、____－2＝4，这几个数依次减少____。
A. He is playing ping-pong.
B. They are climbing trees.
C. She is singing and dancing.
D. I'm doing my homework.
E. It's running on the grass.
下列计算正确的是（ ）
