He could sing( at the age of ) four他参加了那次聚会。He ___ ___ ___ the party.He ( took part in ) the party.他五岁时就会打网球了He ___ play tennis when he ___ ___ .由于风暴，我们只能呆在家里。We had to stay at home ___ ___ the storm.他在北京大学主修英语专业。He ___ ___ English in Peking University.He ( could ) play tennis when he (was five ).We had to stay at home (because of ) the storm. He (major is ) English in Peking University.