A:把横梁右端平衡螺母向右旋出一些
B:把横梁右端平衡螺母向左旋出一些
C:把天平右盘的砝码减少一些
D:向右移动游码
____ is not good to play computer games so much. (That/It)
There used to ____ (be) a lot of manatees. But now there are few.
Children should be taught about ____ (person) safety on the street.