Assertion: orchestra's instrument | /r/HasProperty | needed
Facets:
value: in the case of the trumpet
type: OTHER
Source sentences:
text: But an orchestra can include whatever instruments are needed to perform a musical work.
text: In the case of the trumpet, however, only one instrument is necessary—that in B flat—as its pitch may be instantly lowered to A by drawing a telescopic slide or by employing a special valve mechanism.