Back running
[化] 封底焊
🧩 词语组成解析
back
[bæk]
n. 背，背部;背面，反面;后面，后部;（椅子等的）靠背;
vt. 使后退;支持;加背书于;下赌注于;
vi. 后退;倒退;
adj. 背部的;后面的;以前的;拖欠的;
adv. 以前;向后地;
running
['rʌnɪŋ]
n. 跑步;运转;流出;
adj. 跑着的;流动的;连续的;操作中的，运转着的;
v. 跑;运转(run的ing形式);
🗣️ 情景例句
You were right, Philip.
你说对了。 Philip。
Nothing can shake the basis for my belief.
任何东西都动摇不了我信念的基础。
and we have to lower into the ground and haul out of the ground great lengths of drill pipe which are rotated by an engine at the top and are fitted with a cutting bit at the bottom.
我们必须把很长的钻杆一节节地钻入地下，然后再从地下拉出来。钻杆顶部安装的发动机带动钻杆旋转，它的底部装有钻头。