Assertion: aqueduct | /r/HasProperty | the precursors of such works
Facets:
value: undoubtedly
type: DEGREE
Source sentences:
text: Among the earliest examples of Greek work are the tunnels or emissaria which drained Lake Copais in Boeotia; these, though not strictly aqueducts, were undoubtedly the precursors of such works, consisting as they did of subterranean tunnels ( ὑπόνομοι) with vertical shafts ( φρεατίαι), sixteen of which are still recognizable, the deepest being about 150 ft.