This question may come up as a result of the pandemic. Employers want to know how people used their time differently. Know that you don’t have to feel scared about answering this question if you didn’t spend your time brushing up on skills or taking courses. We learn from any experience we have.
If you spent time honing your professional skills, you might say the following.
Example: “The extra time on my plate really allowed me to get introspective around where I want to take my career. I read a lot of journals to keep abreast of the latest ideas in my field, and sharpened my skills by taking some online courses, such as…” (and then be specific).