Since用法

• Since是從屬連接詞 
•  主要子句用完成式 
•  表時間:

Charlie's English has improved a lot since he moved to the US. Since Ophelia started living on her own, she has become a lot more independent.

• 表原因

Since we are late for the movie, let's take a taxi to the theater. Mable was sleepy in class all day since she went to bed late the previous night.

參考來源: 空中美語
「since」用法教你懂－可以表達時間、也能表達原因的英文單字
https://blog.english4u.net/blog2.aspx?id=254&fbclid=IwAR3AQyDEwMvv0rnk18RWMKupZKMdUrXDYzcbbXpkn9wJxDdA2Jw-k-d8-CA