Substitute teacher Bernadette Martens-Saxelby says filling in on campus in the age of COVID-19 means she has to be in multiple places at once. She is engaging with students on multiple platforms and in several places throughout the day. On Wednesday, she sat in the back of a classroom on the second floor of Lake Travis High School, ready to engage with students in person and online. As more students return to classrooms in the coming days and some teachers raise concerns about coming back amid the coronavirus pandemic, school districts in the Austin area will be calling on substitute teachers to fill the gaps and take on new roles...