The book mainly tells that different countries have different customs.

 ---Is this book Betty's? ----Yes , it's ________. 

 He could play the violin when he was five. 

In some cities, the junior pupils look forward to having ______ time to relax and ______ homework to do.

 — It was a heavy snow last night. Are we all here now? — Yes, and _____ of us was late for school.