关于定语从句的is ( ) some foreign friends who are from Germany visi

把这句改成陈述句来看你就知道了,this school is ...that some foreign friends (who are from germany) visited last week.前面这个学校缺乏了定性的表语,is后面得跟上形容词或者名词,我们平常说That is a book.is的后面得有个宾语,然后才能在后面跟上从句来修饰book这个表语（or宾语）.你的这句话后面的从句缺乏了先行词,当然不行了.