I regretthat we can’t stay here any longer.A. sayingB. having saidC. to saidD. to say

问题补充：

I regretthat we can’t stay here any longer.

A. saying

B. having said

C. to said

D. to say

答案：

A. saying

B. having said

C. to said

(答案→)D. to say

解析：考查非谓语动词。regret to do sth.表示遗憾去做，而未做；regret doing表示后悔去做，意思为“做了”，此处为未做，故答案为D。