—My sister looks very upset. What should I do?

—I think she      happy if you ____a surprise party for her .

A．is; have

B．will be; will have

C．is; will have

D．will be; have

中国第四次民族大融合是在（）。

A.春秋、战国

B.魏晋南北朝

C.清代

D.民国