We prove an easy-witness lemma ($\ewl$) for unambiguous non-deterministic verfiers. We show that if $\utime(t)\subset\mathcal{C}$, then for every $L\in\utime(t)$, for every $\utime(t)$ verifier $V$ for $L$, and for every $x\in L$, there is a certificate $y$ satisfing $V(x,y)=1$, that can be encoded as a truth-table of a $\mathcal{C}$ circuit. Our ... more >>>