题目

It 1__________Sunday today.Early in the morning my 2__________and I went to Xi shan by bus to plant trees.As soon as we got there,we began 3__________.Some were digging,some 4__________(plant),and there were still some watering.5__________of us were trying hard to plant as 6__________as we could.All of us were afraid of 7__________behind.After work,we were wet all over.Looking at the lines of young trees,we forgot our 8__________(tire)We came back at 12.We all think it’s 9__________for us to take part in this kind of physical labor.It not only 10__________students a lot of good,but also bene某人以1米／秒的速度向竖直悬挂的平面镜走去，以他自己为参照物，镜中像的速度是________米/秒．