be afraid doing/to do

　　be afraid to do　不敢，胆怯去做某事，是主观上的原因不去做，意为“怕”；

　　be afraid of doing　担心出现doing的状况、结果。 doing 是客观上造成的，意为“生怕，恐怕”。

　   She was afraid to step further in grass because she was afraid of being bitten by a snake. 她生怕被蛇咬着，而不敢在草丛中再走一步。

     She was afraid to wake her husband. 她不敢去叫醒她丈夫。

   She was afraid of waking her husband. 她生怕吵醒她丈夫。

be interested doing/to do

　　interested to do　　 对做某事感兴趣，想了解某事。

　　interested in doing　 对某种想法感兴趣，doing 通常为想法。

　　I shall be interested to know what happens. 我很想知道发生了什么事。 (想了解)

　I‘m interested in working in Switzerland. Do you have any idea about that？ 我对在瑞士工作感兴趣。你想过这事吗？　 (一种想法)

mean to doing/to do

　　mean to do　 打算、想

　　mean doing　意味着

　　I mean to go， but my father would not allow me to. 我想去，但是我父亲不肯让我去。

　To raise wage means increasing purchasing power. 赠加工资意味着增加购买力。