胃溃疡存在的主要特点是（）

A.胃酸降低

B.贫血

C.胃酸分泌升高

D.两者均无

E.胃酸分泌升高和贫血

—Are you going to have a football game on Saturday ________ on Sunday?

—On Sunday.

A．and

B．or

C．but

D．so