碎石道床线路起道作业需要的工具有:()、道尺、道镐等。
A、起道机
B、弯轨器
C、道尺
D、道镐
参考答案:A, C, D
.Only when Tom fully recovered___________back to work.
A.did he go
B.he went
C.had he gone
D.he had gone