当关井时，柱塞沿生产管柱向下降落。

When the well is shut-in, a plunger is dropped down the production string.

youdao

这只是一次教科书式的沿航线起飞降落的任务。

It's just been a textbook mission up and down the line.

youdao

据BBC报道，这是美国自实施太空计划以来首次使飞机进入轨道，又自动沿跑道降落到地面。

The vehicle is the first in the history of the US space programme to reach orbit and return autonomously to a runway, the BBC reports.

youdao