烟粉虱发生危害及控制技术
1·Nowadays, abaci are often constructed as a wooden frame with beads sliding on wires, but originally they were beads or stones moved in grooves in sand or on tablets of wood, stone, or metal.
如今，算盘往往建造在电线与滑动珠子木框架，但是最初他们是珠子或石头，在沙槽移动或木材，石头或金属片。