Brady Dennis reports on the growing number of cases of the novel coronavirus in the United States. Sarah Kaplan explains the science of why this virus is so dangerous. And, Rick Maese on the Tokyo Olympics, now postponed until 2021. Read more:‘It’s going to get bad’: As outbreak surges, nation faces tough start to a grim week.The science behind what makes this coronavirus so sneaky, deadly and difficult to defeat.The 2020 Olympics will be postponed. We talked to athletes about how they’re feeling.Follow the Post’s live coverage of the coronavirus pandemic here. Subscribe to The Washington Post: https://postreports.com/offer