To the untutored eye the tightly forested Ardennes

To the untutored eye the tightly forested Ardennes hills around Sedan look quite (i) , (ii) place through which to advance a modern army; even with today’s more numerous and better roads and bridges, the woods and the river Meuse form a significant (iii). Blank (i): impenetrable, inconsiderable, uncultivated Blank (ii): a makeshift, an unpropitious, an unremarkable Blank (iii): resource, impediment, passage