---What did the boy do just now?---He ran the road to pick up his ball.A. acrossB. through

问题补充：

---What did the boy do just now?

---He ran the road to pick up his ball.

A. across

B. through

C. by

D. for

答案：

(答案→)A. across

B. through

C. by

D. for

解析：across横穿，穿过；through通过，穿过；by 通过，被；for为了，对于。句意：刚才这个男孩做了什么？——他横穿马路去捡他的球了。结合语境可知选A。