-Was the United State of America founded on July 4th 1776？You be right but I need to

问题补充：

-Was the United State of America founded on July 4th, 1776？

--You be right but I need to check it in the history textbook anyway.

A. have to

B. must

C. may

D. will

答案：

A. have to

B. must

(答案→)C. may

D. will

解析：句意：--美国成立于1776年的7月4号吗？--你可能是对的，但是我需要核实历史书。从but I need to check it in the history textbook anyway.可知说话的人不太确定，用may可能，可以，have to不得不，must必须，will将会，所以选C。