i would appreciate it if you let me get on with my job、it 可不可以改为that

（1）it不可以改为that。原因是appreciate+it+when（if）+从句这个句型中，it是做形式宾语的成 分，that不可以作形式宾语，类似的动词还有like、dislike、enjoy、love、hate、prefer等。

再举一个例子：

I really hate it if my mom sends me to a school which I don't like at all.

（2）尽管that听起来是对的，但根据语法它是错的。如果非得要用that，可以换成这样：

A：I will let you get on with your job，jerry.

B：I really appreciate that，Tommy.（此时that指代前面那件事）