With the COVID-19 outbreak, emergency remote teaching -- an unprepared distant mode of education became the only possible alternative for schools. The present large-scale survey with 3,672 Grade 3 and 9 students, their parents, and 863 teachers/principals was conducted in the metropolitan city of Hong Kong after half a year of school lockdown. Results showed teachers, principals, and parents were worried about students' inability to concentrate and learn without teachers' explanations. In contrast, students, particularly younger ones, were less affected. They perceived their academic achievement was not worsened and they were more lively. Generally, lack of computers and stable internet was not seen as problems. Notably, socially disadvantaged students were not different in their perceived challenges, affects, life satisfaction, or perceived academic achievement. For cities with adequate provision of computers and internet facilities, the pandemic probably forced a positive and giant leap in using advanced technologies and pedagogies.