Since they changed jobs, their life _____ been much easier.has还是had?

Since they changed jobs, their life _____ been much easier.has还是had? Since they changed jobs,their life _____ been much easier.A.areB.wasC.hasD.had My hometown has changed g_ since 1990. My hometown has changed ___ (great) since 2000. 翻译;Mr.Hardy,has the situation changed since last night? Nanjing changed a lot in 2004.(用since改写) there is nothing changed since i left here.此句中changed的用法 改为一般疑问句The place has already changed since then.（ ）the place （　）since then( ) 分析英语句子成分In order for the structure to achieve the size and strength necessary to meet its purpose,architecture employs methods of support that,because they are based on physical laws,have changed little since people first discovered t It _____ a lot since I left the city.A.is changing B.changes C.changed D.has changed The life we were used to _____ greatly since 1992.A.change B.has changedC.have changed D.changed The life we were used to——greatly since 1992.Bhas changed Cchangeing Dhave changed为何选B The country life he was used to____greatly since 1992A.change B.has changed C.changing D.have changed The life people were used to _____ since the earthequake happened in Wenchuan.A changed B.changing C.has changed D.having changed请告知理由谢谢 The town a lot since i was there in 1980a:has changed b:was changing c:had changed d:has been changed The life he was used to( has changed )greatly since 1992,为什么括号里是has changed ,而不填have changed ,change changing 完成时语法问题she has changed a lot since the last time i saw her-she looks much older.为什么用has changed不用had changed. That’s changed since I was here.That’s changed since Iwas here.这个句子中,'s可以改成was么?为什么？