—What a pity! Their experiment is a failure.

—They ________ better under more favorable conditions.

A．should have done

B．could have done

C．must have done

D．may have done

鼻腔前下方出血（）

A.鼻腔烧灼

B.切开引流，行前鼻腔填塞

C.前后鼻孔填塞

D.后鼻孔填塞

E.切开引流，行鼻腔填塞