Her mother has been ill（ ） she came to Beijing last week A.since B.as C.until D.When
问题描述：
Her mother has been ill（ ） she came to Beijing last week A.since B.as C.until D.When
答
应该选 A
现在完成时 +since +一般过去时
自从上周她来北京以来她妈妈就病了.