Many drugs were found by trial and error
很多药物都是通过反复试验才发现的。
We plan to release a prototype this autumn for trial in hospitals.
The system was introduced on a trial basis for one month.
这个制度已引进试行一个月。
The date of the trial has been advanced by one week.
审判日期提前了一星期。
The trial is expected to continue for three months.
预计审判要持续三个月。