全国大众英语测验语法——beafraiddoing/todo
be afraid to do不敢，畏惧往做某事，是主不雅观上的缘故原因不往做，意为"怕"；
be afraid of doing担心出现doing的状况、功效。 doing是客不雅观上形成的，意为"生怕，生怕"。
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.
她不敢往叫醒她丈夫。
She was afraid of waking her husband.
她生怕吵醒她丈夫。