since可以引导时间状语从句和原因状语从句.不能引导定语从句.
引导时间状语从句一般放在后面.指从说话前某一时刻到说话时刻这一段时间.常用于完成时态.He has been living in Beijing since he was five.五岁后一直住在北京.
I have learned English since you left.你走了以后我就学了英语.
引导原因状语从句,主要是说明已知的必然性理由.只能放在前面引导,不能出现在后面.在后面常用as.Since you are ill,you had better not go to school.既然病了,就别去学校了.另外记住,because常用来引导未知性必然理由. since可以引导时间状语从句和原因状语从句.不能引导定语从句.
引导时间状语从句一般放在后面.指从说话前某一时刻到说话时刻这一段时间.常用于完成时态.He has been living in Beijing since he was five.五岁后一直住在北京.
I have learned English since you left.你走了以后我就学了英语.
引导原因状语从句,主要是说明已知的必然性理由.只能放在前面引导,不能出现在后面.在后面常用as.Since you are ill,you had better not go to school.既然病了,就别去学校了.另外记住,because常用来引导未知性必然理由.