Since 和 for 的用法及区别： 一，since 的四种用法 1，since + 过去一个时间点（如具体的年、月、日期、钟点、ago. 1990 , last month , half past six I have been here since 1990. 1990起，我一直在这儿。 2，since+ 一段时间+ago I have been here since five months ago。自从五个月前，我已经在这儿了。 3，since+从句Great Changes have taken place since you left. 自从你走后，已经发生了很大的变化。 4，It is +一段时间+since从句It is two years since I became an English teacher. 我成为英语老师有两年了。 二，Since 和for区别1，Since +时间点，具体时间“自从、以来，从、以后” 用来说明动作起始时间I have been in Bei
