Looking on the internet deeply has found these results:

I'll be teacher in today's class is the most popular phrase on the web.

I'll be teaching in today's class 15 results on the web	I'll be teacher in today's class 1222,000,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Unfortunately, students, I will not be teaching class today. These skills are the skills we should be teaching in the classroom as well as everything else. Then you need to be teaching in both languages from now on. Now, this is the stuff they should be teaching in the army. And I'll be teaching Acting for Soap Operas. You shouldn't be teaching in Ithaca. Interesting development in today's press, ma'am. Looks like I'll be teaching at a Catholic high school.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

I'll be teaching in today's class

15 results on the web

I'll be teacher in today's class

1222,000,000 results on the web

More popular!

Unfortunately, students, I will not be teaching class today.
These skills are the skills we should be teaching in the classroom as well as everything else.
Then you need to be teaching in both languages from now on.
Now, this is the stuff they should be teaching in the army.
And I'll be teaching Acting for Soap Operas.
You shouldn't be teaching in Ithaca.
Interesting development in today's press, ma'am.
Looks like I'll be teaching at a Catholic high school.

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.