初二英语的一个句子 求翻译As I'm sure you know by now,our favorite teacher,Ms.Steen,is leaving soon to go back to the US.请问最开头是什么意思,这又是什么句式?

初二英语的一个句子 求翻译As I'm sure you know by now,our favorite teacher,Ms.Steen,is leaving soon to go back to the US.请问最开头是什么意思,这又是什么句式?
初二英语的一个句子 求翻译
As I'm sure you know by now,our favorite teacher,Ms.Steen,is leaving soon to go back to the US.
请问最开头是什么意思,这又是什么句式?

初二英语的一个句子 求翻译As I'm sure you know by now,our favorite teacher,Ms.Steen,is leaving soon to go back to the US.请问最开头是什么意思,这又是什么句式?
As I'm sure you know by now,our favorite teacher,Ms.Steen,is leaving soon to go back to the US.
目前我很确定你知道,我们最喜爱的老师,Steen老师,马上就要回美国去了.

正如我所确定你现在已经知道，我们最喜爱的老师Ms.Steen不久就要离开回美国了

我肯定你知道号码。