PWS-33 Wyżeł
...that only two prototypes of PWS-33 Wyżeł, a Polish trainer aircraft, were built before the production was interrupted by German invasion of Poland?
...that only two <a href="./Prototype" id="mwwQ" rel="mw:WikiLink" title="Prototype">prototypes</a> of <b id="mwwg"><a href="./PWS-33_Wyżeł" id="mwww" rel="mw:WikiLink" title="PWS-33 Wyżeł">PWS-33 Wyżeł</a></b>, a <a href="./Second_Polish_Republic" id="mwxA" rel="mw:WikiLink" title="Second Polish Republic">Polish</a> <a href="./Trainer_aircraft" id="mwxQ" rel="mw:WikiLink" title="Trainer aircraft">trainer aircraft</a>, were built before the production was interrupted by <a class="mw-redirect" href="./Invasion_of_Poland_(1939)" id="mwxg" rel="mw:WikiLink" title="Invasion of Poland (1939)">German invasion of Poland</a>?