Assertion: cello's string | /r/HasProperty | pressed by the fingers of the left hand
Facets:
value: to control vibrato
type: PURPOSE
value: to control the pitch
type: PURPOSE
Source sentences:
text: The strings are pressed by the fingers of the left hand to control the pitch and vibrato, and to create effects such as trills, finger tremolo, glissando, multiple stops, and portamento.