since
1
自从, 自...以来
used to express a period from a specific past time up to now or another specified point
- I've felt better since I've been here.
我来到这里之后感觉好多了。
- I've been very tired since I started the new job.
自从我开始新工作以来，我一直很累。
- I have lived in this city since I moved here for my job.
我自从为了工作搬到这里以来，就一直住在这个城市。
- He has improved a lot since he started training.
他自开始训练以来进步了很多。
- I have enjoyed traveling ever since I was young.
我自从年轻时就喜欢旅行。
2
自从
used to indicate a point that marks the beginning of an ongoing condition
- I have been feeling much better ever since I started exercising regularly.
自从我开始定期锻炼以来，我感觉好多了。
- She has been working at the company ever since she graduated.
她自从毕业以来一直在公司工作。
- We have been waiting here since 3 PM.
我们从下午3点就一直在等。
- He has been teaching ever since he finished his studies.
他完成学业以来一直在教书。
- They have been working on this project ever since last month.
他们从上个月开始就一直在做这个项目。
同义词：
3
因为, 既然
used to express a reason for something
- I didn't eat dessert since I'm on a diet.
我没有吃甜点，因为我在节食。
- She couldn't attend the party since she had a prior commitment.
她没能参加派对，因为她事先有约。
- She couldn't call him since she lost her phone.
她因为丢了手机，所以不能给他打电话。
- They couldn't go to the concert since they didn't have tickets.
他们没能去听音乐会，因为他们没有票。
- They didn't go on the trip since they couldn't afford it.
他们没有去旅行，因为他们负担不起。