在图中画出物体A所受重力G的示意图.
图中已给出重心,从重心开始竖直向下作一条带箭头的线段,并标出G.
故答案为:
I____English for six years.[ ]
A. have learning
B.have learned
C. began to learn
D.learned
输入网址到网页打开数据经过的过程