GRE Text Completion: JiJing 1373-GRE填空机经1373题 - MQ50FCIAE06_E7G1A

In medieval Europe, watermills were more (i)____________ than windmills. It is true that windmills could be built virtually anywhere, whereas watermills (ii)____________. However, watermills' greater capacity and reliability provided a better (iii)____________ the money required to build the mill. A. problematic B. were suitable only for certain locations C. source of D. profitable E. inspired a variety of new technologies F. adjunct to G. versatile H. required a good deal of upkeep I. return on