Chicago will teach online only when school resumes in September, the mayor said on Wednesday, and New York City announced checkpoints at bridges and tunnels to enforce a quarantine on travelers from 35 states on a list of coronavirus hot spots. The teachers’ union and many parents in Chicago had objected to a plan to allow students the option of attending class in pods of 15 pupils twice a week. Local media reported that the Chicago Teachers’ Union had called for a strike vote over the issue. […] Los Angeles has already announced that students will be kept home, while...