bottom bench
... bench 平台,工作台,台座;阶地,台地;海蚀平台 bottom bench 下分层;下台阶 canyon bench 峡谷阶地 ...
Give a way out
... give-way vessel 让路船 Give a way out 下台阶 Give-way marking 让路线 ...
walk up / down the steps
Mattie Tyce
benching tunneling method