Starting2001,1 st through4 th grade students will be required to take two hours of mother tongue courses per week; but they are only electives from the5 th grade on.是什么意思_Starting2001,1 st through4 th grade students will be required to take two hours of mother tongue courses per week; but they are only electives from the5 th grade on.在線翻譯_英語_讀音_用法_例句