Kate has made many friends________she came to our school.
问题描述：
Kate has made many friends________she came to our school.
A before B after C since D until
我知道选c,但我疑惑为什么不选b
答
C
has made 是完成时,since它的标志.这句话翻译过来是“凯特来我们学校前已经交了很多朋友.”选B就成了“凯特来我们之后交了很多朋友.”