Heating-oil prices are expected to be higher this year than

[WendyH75]

2018 Ver - Pg701 #772
[Question text removed]

Answer a d, last word is "were" whereas answer b c d, last word is "did"; when I was doing this question, I thought "...are paying about $5 a barrel...." should be paired up with "were" instead of "did"; Manhattan Prep answer guide didn't address this. Is that an issue? Or the grammar is correct.

[Sage Pearce-Higgins]

You can't post problems from the Official Guide here as they are copyright. Please read the forum guidelines before posting.

The split between 'were' and 'did' (what we call 'helper verbs') is a controversial one. I agree with you that 'were [paying]' seems better as it's parallel with 'are paying'. However, looking at this thread (particularly the GMAT Prep problem) convinced me that GMAT doesn't always follow this rule: https://www.manhattanprep.com/gmat/foru ... ml#p128802