  Notice the following anomaly which can arise in an infinitary language but not in a finitary one. In the language  L(ω1,ω), which allows countably infinite conjunctions but only finite quantifications, there are preformulas with so many free variables that they cannot be “closed” into sentences of  L(ω1,ω)  by prefixing quantifiers. Such is the case, for example, for the  L(ω1,ω)-preformula