If something happens during a period of time or an event, it happens continuously, or happens several times between the beginning and end of that period or event.
Sandstorms are common during the Saudi Arabian winter.
在沙特阿拉伯,冬季期间沙暴很常见。
If something develops during a period of time, it develops gradually from the beginning to the end of that period.
Wages have fallen by more than twenty per cent during the past two months.
在过去的两个月期间工资已下降了二十多个百分点。
An event that happens during a period of time happens at some point or moment in that period.
During his visit, the Pope will also bless the new hospital.
访问期间,教皇还将为新医院祈福。