For example, viruses are emerging more frequently than ever before. Forty years ago, around two new viruses were discovered every decade. Now the figure is more like two new viruses per year.

For example, viruses are emerging more frequently than ever before. Forty years ago, around two new viruses were discovered every decade. Now the figure is more like two new viruses per year.

比如说，新病毒的出现较从前更加频繁。40年前，每10年中大约有两种新病毒被发现，而现在差不多每年就有两种新病毒出现。