 From Britain to New Zealand, schools around the world are closing due to the coronavirus outbreak. Many teachers are turning their hands to online tutoring, like here in the Philippines, where tens of thousands of teachers are logging on - and cashing in on the overtime. They are buckling down in their homes to teach conversational, travel, and business-levels of English. And their students range from grade schoolers to working professionals in countries like Japan and China. Raven Kate De Leons lessons are hugely in demand. Shes spending up to 10 hours a day at her computer. SOUNDBITE English ONLINE ENGLISH TEACHER, RAVEN DE LEON, SAYING: As a teacher Im also as I have said Im very happy. Its a great opportunity for me to earn a lot, but then Im also thinking of the welfare of my students here. As much as possible Im optimistic that everything will be alright soon, that these negative situation will soon end. China shut down its schools in February to contain infections. With lockdowns giving many the free time to improve their English, companies like 51Talk of China Online Education Group and RareJob Philippines have seen demand soar since then - bucking the devastating effect on the worlds economies from coronavirus. 51Talk charges around 6 for a 25-minute session, with teachers earning around 2.50 per hour. More than two dozen countries have followed Chinas lead, sending more than 290 million children out of school, according to UNESCO data. 