The trial was conducted under a blanket of secrecy.
审讯在高度保密下进行。
《牛津词典》
2
What those early craftsmen had found by trial and error was that under pressure a pagoda's loose stack of floors could be made to slither to and fro independent of one another.
"那些早期的工匠通过反复试验发现：在压力作用下，宝塔松散堆叠的楼层可以彼此独立地来回滑动。
3
Robots are currently under a two-year trial in Wales which will train "farmbots" to herd, monitor the health of livestock, and make sure there is enough pasture for them to graze on.