Notes: The PWC form must be analysed as consisting of the old class marker *d- + the root, with subsequent metathesis of glottalisation (*ṭǝʁʷa- < *d-ǝq̇ʷa-). The EC-WC comparison seems quite plausible phonetically and semantically.
In EC the root interacts actively with *=arq̇Vr 'to reach' and *=ǝ̆q̇wVn 'to be enough, sufficient', but there seems to be a good reason for keeping all these three roots apart.