抗原的基本性质是()

A．异物性和特异性

B．免疫原性与免疫反应性

C．抗原性与异物性

D．理化复杂性与特异性

E．异物性和免疫反应性

(2013 ·陕西宝鸡二模)—You don't seem to be quite yourself today.What's wrong?

—Oh, I'm suffering from a cold.Nothing serious ________.

A．yet

B．indeed

C．though

D．anyway