"He did everything except mow the grass"
Isn't the bold word supposed to be mowing? It was a multiple choice question and my instructor said the answer is "mow". Why is that?
Except is usually followed by an '-ing form: Don't think about anything except having a good time.
However, we use a bare infinitive for constuctions with Do ... except: She hasn't done anything except complain since she got here.
Context is always important; labelling is rarely important.
***** NOT A TEACHER *****
(1) May I share some information with you that may explain why your teacher gave "mow" as the correct answer?
(2) The great grammarian George O. Curme in his two-volume masterpiece gives this
sentence (I have copied it exactly as he wrote it, including the parentheses and the brackets):
I will do anything to show my gratitude but (or except) [that I do] marry the daughter.
I guess that the sentence above is a beautiful way of saying something like:
I will do anything to show my gratitude, but there is one thing that I will not do: marry the daughter.
(3) Thus, it is only my opinion that your teacher's "complete" sentence is:
He did everything except [that he did] mow the grass.
(He did everything, but there is thing that he did not do: mow the grass.)