“由于”这个词如果放在句首用什么英文单词比较好？

Becasue (of) ...
Due to...
Becaue of/(Due to) my mistake, we lost the opportunity.

As...
As you are busy, I’ll go out by myself. 既然你很忙，我就单独外出吧。

Since...
Since the problem hasn't been sloved for such a long time, we have to escalate it to higher level. 由于这个问题长时间没有得到解决，我们只好向更高一级报。

as

Now that...
Because of...

since

due to/owing to/on account of

because