关于他是否会参加活动，存在很多不确定性。

There was a lot of ___uncertainty about whether or not he would attend the event.

生活充满了不确定因素。

Life is full of ___uncertainties.

基本商品的短缺使我们的生活充满了不确定性。

Shortages of basic goods have made our lives full of ___uncertainty.