21.my sister has been studying for a test____a week.

21.my sister has been studying for a test____a week. He has been studying for the past week to get ready for the my sister has been in Hefei for three years.she()French in A My sister has been in America for half a year.She _____ the My sister has been working for this firm 与My sister has alre It has been raining for nearly a week His father has been away from Beijing for a week. My sister has been working ()western China since graduated.A my sister has been engaged for two months中为什么要用been? 英语翻译What has been needed is a method for studying the detect He has only been studying for a year,but already his English 句型转换The dog has been dead for a week.A week __ __ since the