In the past hundred years,there have been frequent natural disasters worldwide,such as floods,droughts,typhoons,earthquakes,landslides,forest fires,or which some are made worse or even caused by human activities
这里的or which是打字错误吗，假如不是，or which 是什么使用方法呢？
显然是打字错误，or 应为 of：
In the past hundred years, there have been frequent natural disasters worldwide, such as floods, droughts, typhoons, earthquakes, landslides, forest fires, of which some are made worse or even caused by human activities.
【翻译】在过去的一百年里，世界各地频繁发生自然灾害，如洪水、干旱、台风、地震、山体滑坡、森林失火，其中有的自然灾害是因人类活动而变得愈加紧急，甚至由其直接致使的。
of which some = some of which
