looking for an adverb

I think it should be

Two teachers teach lessons to the class alternately

OR

Two teachers teach alternate lessons to the class

Two teachers share in the teaching of the class, alternating lessons.

If you want to complete the sentence as is, with one adverb at the end, I would suggest-- 'rotationally':

Two teachers teach the class rotationally.

Of course, as implied above, you'd be hard pressed to find the adverb rotationally actually used by a native speaker to convey this idea. Even uglier might be '...teach the class sequentially'.

My feeling is always to use something that someone might say - 'Two teachers teach the class in rotation'. Quite nice.

Was there something wrong with "alternately"? I thought that was the obvious choice. Somehow "in rotation" suggests more than two to me (at least, once I get rid of the image of a single teacher spinning in place while teaching the class). Baseball players go to bat in roation, but Mom and Dad alternate in getting up at night with the baby. If there were three teach

I agree with you, Khoff, and disagree with myself. I can't remember now what problem I initially had with 'alternately'.

Maybe I thought 'alternately' suggested that the second teacher was going to teach the same lesson backwards...and make a palindrome out of the course.

Turn taking is the best (though 'actually in informal speech' sound a bit formal to my ears), but seems kind of different from what was asked for. The best adverb is er.. alternately. Very nice. Good work. Sorry.

(I do think '..teach in rotation' would be used, incidentally. )

Or if they do indeed alternate (i.e. Teacher A takes lesson 3, Teacher B takes lesson 4, etc.), you could say "turn and turn about".

MrP

I agree with you, Khoff, and disagree with myself.

Wow! I didn't know I was so persuasive!

Now you mention it, it does sound a little old-fashioned. (Already! And I only posted it half an hour ago.)

MrP