Anyway, here is what I think.
a. Which grammar teacher did she forget the answer in front of? correct
b. Which vacation did John become ill during?
c. Who did you destroy a picture of?
d. I was astonished at the patience she spoke with.
e. What do you eat salad without? not correct
f. What do you eat salad with? correct
g. The cheerfulness which she spoke with of the sad contrasts of her life. awkward
h. The tone which she spoke with thrilled through me.not correct
i. Which vacation did John go to Hawaii during?
j. Who did you destroy a picture of?
k. Which act did John leave the theater after?