10﹣8.7=
1.25×4=
0.013÷0.13=
3.2×9+3.2=
4.36×2.7×0=
0.12=
--- Where's your cousin?
--- He his homework in his bedroom.
如图,试根据下列要求,把被遮挡的部分改为虚线.
(1)AB没有被平面α遮挡;
(2)AB被平面α遮挡.