VC is used mainly to connect clauses to various words when they act as a subordinating conjunction. It is quite similar to the MVs connector, which is used in many similar situations, however, the VC link is "tighter", in that it must always for a cycle with som other link, typically either X or CP. By contrast, the coordinating conjunctions primarily use the Xx connector.
+----------Xs---------+ +----->WV----->+ +-------CV----->+ +--Wd--+--Sp*i-+--VC--+Cs+-Sp*i+---I--+-Ox-+ | | | | | | | | LEFT-WALL I.p stayed.v-d so I.p could.v see.v youVC is used for coordination only, and it links to the head-verb of the previous clause. This is consistent with how subordinating conjunctions are linked, such as "when" and "after". See "W: Coordinating Conjunctions"; and also the coordination overview.
+--VCq--+-SI-+ | | | I would do it, were it possibleHere, VCq is used. Instead of linking to the subject of the following clause, the VCq links to a following auxiliary (either "had" or "were"), which is then forced to use an "SI*j+", creating subject-verb inversion. Conditional expressions can also be used as openers in this way: "Had you been there, I would have seen you". For this, COp is used. For this purpose, "had" and "were" have a special "SI*j+ & (VCq- or COp+)" expression.
+----------------->CPu----------------->+ +----->WV----->+---VCz---+------CV----->+ +->Wd--+---Ss--+ +-Xd+-Sa*a+---Pv---+ | | | | | | | LEFT-WALL she failed , as was hopedHere, the CPu link connects from the left wall to the verb expressing the desire. It forms a cycle with VCz, although it depends on the head-verb connectors WV and CV to accomplish this. The CV link in turn forms a cycle, using the unusual Sa link to "as", in place of the missing subject doing the hoping.