18. 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
then到底是做甚么词啊 谢谢 | 
