插入语“值得注意的是”,用英语怎么说?

一般用相关句型表达：
1.It is a remarkable fact that...
2.It is noteworthy that ...
3.It is rather remarkable that...
4.It's important to note that...
5.It is worth while to note that ...
6.It's worth nothing that...
许多网友会心存疑惑,我列举的是插入语吗,我列举的是 I am sure,I' afraid,等 都是插入语（插入句）

what is observed
我现造的。。。。

worthy of remark is