All but three border crossings between Hong Kong and China will be closed from midnight Tuesday, the city’s leader has announced. Carrie Lam said Monday that the main land borders to mainland China will be shut down, as will the major Hong Kong-Macau ferry terminal. It’s the latest measure to help prevent further spread of the deadly coronavirus. The city’s international airport, the Shenzhen Bay border, and the Hong Kong-Zhuhai-Macau Bridge will all remain open for the time being. Lam’s announcement came after hospital workers in Hong Kong began a strike Monday to demand a full border closure. But Lam insisted border closures were unrelated to the strike. “This has nothing to do with the five-day strike by health-care workers,” she said. “If anyone thinks that by resorting to such extreme measures the government will be made to do something that... will only harm the public, they will not get anywhere.”