可以 didn't use to 和use not to 現(xiàn)在不區(qū)別了
in front of a group這個怎么說 嗯太直白了 有點中式的感覺最好用in the public situation為什么be afraid of不用be afraid to我覺得to do 也可以 不過你要是真較真的的話這題應該用to do 這兩個還是有一定區(qū)別的 be afraid of doing指擔心不利于自己的事發(fā)生 ，側(cè)重于一種結(jié)果be afraid to do 單純的指膽小，害怕,不敢去做某事舉個例子：He was afraid to walk along the banks ,as he was afraid of falling down the river.不過很少有人分得這么仔細，就好比like to do,like doing 很少有人區(qū)別一樣