trial/ 'traɪəl /

1.noun [c/u] [法] 
审理

2.noun [of machine] [ drug etc] 
试验

3.n pl
trials (ordeal) 麻烦

horse trials
马术比赛
trial by jury
陪审团审理
to be sent for trial
送审
on trial
 [法] 受审
4.n pl
(on approval) 试验

by trial and error
反复试验