The scientists are expected to ______ some new suggestions on treating A(H1N1) flu spread all over the world after reading all the materials.

A．keep up with

B．put up with

C．look up to

D．come up with

混合痔是指

A．两个以上内痔

B．两个以上外痔

C．内外痔同时存在

D．内痔多发，形成环状痔

E．直肠上下静脉丛彼此相通形成的痔