They love their daughter so much that they are always ready to do everything they can ________ her happiness.

A．to make sure of

B．make sure of

C．be sure of

D．to be sure of

毛 * * 在《矛盾论》中提出“马克思主义的活的灵魂”是指：（）

A.矛盾的同一性和斗争性的关系

B.内因和外因的关系

C.一般和个别的关系

D.具体地分析具体的情况