Seven-year-old Sophia Cheung knows what to do when she hears a truck arrive outside her home in Hong Kong.She collects her sheet music and runs out the door.Inside the vehicle, music teacher Evan Kam stands by a piano.He holds a container of alcohol-based hand cleaner and wears a protective face covering.Schools in Hong Kong have been closed since late January because of the coronavirus outbreak.Students have been asked to take classes online.But that does not work very well for piano lessons.Ming's Piano, a music school with 12 teachers and about 200 students,is using three trucks to help bring lessons to students' homes.The effort helps keep the business in operation.For students like Sophia, the lessons are a rare and welcome chance to get out of her home.Her mother, Wendy Yeung, said, "I feel very depressed myself, not to mention my children...They are always asking: ‘When can we go out to play? Where can I go? What else can I do?'""Now," she said, "we have an option."Ming's Piano lost more than two-thirds of its business after the outbreak.Many of the school's students wanted to continue with music lessonsbut did not want to use up masks or take public transportation, said Jessica Lam.She is the business development manager for Ming's Piano.The school took its business on the road in late February.It is now operating at 70 percent of its pre-outbreak levels.The piano gets cleaned between lessons.The truck is equipped with an air cleaner and lighting, which means the engine has to be running.As the truck's engine makes a soft noise under her feet,Cheung works on the song she likes most -- "Let it Go", from the Disney movie "Frozen."On this day, she plays with both hands, an improvement from last week.Her teacher, Kam, shows his approval.Outside, cars speed by.Sometimes, people walking by the truck try to have a look inside.Kam said helping students learn to make small improvements would have been difficult through a video lesson.Teaching in a truck feels the same as teaching in a music studio, Kam notes.Kam said he visits six or seven students a day,including some new students living in villages far away from populated areas.Kam said, "Distance is not a limit."