If the engineering feats of that early decade remains impressive – boring a mile-long tunnel through a solid mountain, and turning the eastward flow of two rivers westward – the arduous conditions in which the engineers worked are no less remarkable.
A. If the engineering feats of that early decade remains impressive – boring
B. If the engineering feats of that early decade remains impressive – such as the boring of
C. Although the engineering feats of that early decade remains impressive – boring
D. If the feats of engineering in that early decade remains impressive – boring
E. If the engineering feats of that early decade remain impressive – boring
A. If the engineering feats of that early decade remains impressive – boring
B. If the engineering feats of that early decade remains impressive – such as the boring of
C. Although the engineering feats of that early decade remains impressive – boring
D. If the feats of engineering in that early decade remains impressive – boring
E. If the engineering feats of that early decade remain impressive – boring













