be afraid doing/to do
be afraid to do 不敢，膽怯去做某事，是主觀上的原因不去做，意為"怕"；
be afraid of doing 擔心出現(xiàn)doing的狀況、結果。 doing 是客觀上造成的，意為"生怕，恐怕"。
She was afraid to step further in grass because she was afraid of being bitten by a snake.
她生怕被蛇咬著，而不敢在草叢中再走一步。
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 afraid to do 不敢，膽怯去做某事，是主觀上的原因不去做，意為"怕"；
be afraid of doing 擔心出現(xiàn)doing的狀況、結果。 doing 是客觀上造成的，意為"生怕，恐怕"。
She was afraid to step further in grass because she was afraid of being bitten by a snake.
她生怕被蛇咬著，而不敢在草叢中再走一步。
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。