Quote:
799. The owner of Steele’s Grocery in Osage, Ohio, saved $600 monthly on heat during the winter by putting all his refrigerator air compressors together in an insulated compartment, then installing two fans and a duct that carried waste heat from the compressors into the main part of the store.
(A) then installing two fans and a duct that carried
(B) then he installing two fans and a duct that carried
(C) then two fans were installed with a duct that carried
(D) installing two fans, and then carrying through a duct
(E) installing two fans, and a duct carrying
Please, explanations ONLY
Even though you want explanations only, i'll clarify that my choice is A.
Now for my reasoning...
Upon first glance I'd eliminate choice B and C.
(B) "then he installing two fans" is awkward
(C) "then two fans were installed" is past tense. The sentence should describe what the owner did to save the $600--by putting X...installing Y...
Eliminate (D) for the last part of the clause: "...carrying through a duct waste heat..."? Should be "carried".
Between A and E now.
Eliminate (E) because it is structured as a list but the last part of the list doesn't work. Putting...,installing...,and a duct? Nope.
Left with A. A tells us he saved dough by putting in x and installing n and m that carried waste heat...
Sentence A provides us with a correctly placed restrictive clause for m (aka a duct).