a bit +形容词或副词原级或比较级,a bit不可以接名词,
而a bit of +不可数名词.
sure做形容词,be sure of 对什么肯定的意思
在句中作表语
eg:i,m sure of that
sure做副词,be sure to do sth 不要忘了做某事的意思
eg:be sure to close the window 这是一个命令语气.
be afraid to do sth
be afraid of doing sth
be afraid of sth
be afraid of (that) .i am afraid to ride bike.
i am afraid of riding bike.
i am afraid that i will never see you