What English sentences are represented by the following expressions?
(a) $\neg(P \wedge \neg S)$, where $P$ stands for the statement "I will buy the pants" and $S$ stands for the statement "I will buy the shirt."
(b) $\neg P \wedge \neg S$, where $P$ and $S$ mean the same thing as in (a).
(c) $(S \vee G) \wedge(\neg S \vee \neg G)$, where $S$ stands for the statement "Steve is happy" and $G$ stands for "George is happy."
(d) $[S \vee(G \wedge \neg S)] \vee \neg G$, where $S$ and $G$ mean the same thing as in (c).