is, are, was, where, which, whose Since a staple of immigrant co

is, are, was, where, which, whose Since a staple of immigrant communities in big cities ______ long, restaurants______ diners chop, grill, boil or dip their food are hot in the American heartland.
【正确答案】：are; where
【题目解析】：第一个空格考查的是主谓一致，主语communities是复数所以用are，第二空是考查的关系分句。分句的意思是在餐馆里用餐者剁、烤、煮、蘸着食物吃，所以用关系副词，相当于in which。