President Biden has returned to strict isolation after testing positive for COVID again.

在新冠病毒检测再次呈阳性后，拜登总统重新进行严格隔离。

Experts say the current food shortage is likely due to complications from the COVID pandemic, three years of closed borders and strict isolation, as well as floods and storms, which offset planting.

专家表示，目前的粮食短缺可能是由于新冠疫情、三年的边境封锁与严格隔离措施，以及影响种植的洪水与风暴等复杂因素造成的。