Assertion: tube | /r/HasProperty | possible
Facets:
value: to switch off one module
type: PURPOSE
Source sentences:
text: In 1934 Flowers built a successful experimental installation using over 3,000 tubes in small independent modules; when a tube failed, it was possible to switch off one module and keep the others going, thereby reducing the risk of another tube failure being caused; this installation was accepted by the Post Office (who operated telephone exchanges).