由于健康状况，他不能吃乳制品。

He can't eat dairy ___on ___account ___of a medical condition.

由于天气不好，野餐被取消了。

The picnic was cancelled ___on ___account ___of the bad weather.

由于大雾，许多航班延误了。

Many flights were delayed ___on ___account ___of the heavy fog.