因为她从来不接我的电话,所以我必须要写信给她
since有因为,自从的意思,可放句首或句中,一般可将两分句调换Since为什么要放在前面而不是放在中间呢？可以放中间，句子可变成i will have to write to her since she is never in when i phone 两个分句可调换顺序