用be able to do be afraid of sth allow sb to do ask to do 用这些

用be able to do be afraid of sth allow sb to do ask to do 用这些 英语翻译allow sb.to do sth.ask sb.to do sth.be busy doing sth.be ask sb to do sth be afraid of doing be busy doing be late fo 用allow sb to do sth 和be allowed to do sth造句 各三句 用be able to do sth造句 用be afraid to do sth造句 be afraid to do sth be afraid of doing sth be able to do sth 用allow sb to do sth 造句 I imagine sb.to be able to do sth. be allowed to do sth和allow sb to do sth有什么区别?怎么运用? 一个英语的问题.就是allow to do .allow doing .allow sb to do sth.sb be