语法与词汇11.Jean Wagner's most enduring contribution to the study of Afro American poetry is his insistence that it ______ in a religious, as well as worldly, frame of reference.
【正确答案】
A
【答案解析】is to be表示应该，必须做的事。have done表示完成；should have done表示本来应该做而没有做的事。故选A。