By the end of the day we were tired but happy.
一天结束时，我们很累，但很高兴。
I always leave a clear desk at the end of the day.
每天工作结束时，我总是把桌上收拾干净不放任何东西。
The new model will be in production by the end of the year.
新型号将于年底投产。
We had come to a dead end in our research.
我们的研究工作已陷入绝境。
I'm sure you'll get there in the end.
我相信你最终会成功的。