Choose the correct answer to complete each of the blanks in the passage.
The stethoscope is a common instrument to all doctors. This instrument may even be considered as the symbol of medicine. The (12) __________ of the stethoscope is René-Théophile-Hyacinthe Laennec (1781 – 1826). He was a French doctor (13) __________ invented the stethoscope in 1816. Here is the story of how this remarkable medical invention came to be. In September 1816, during a cool morning, (14) __________ walking in Paris, Dr. René, observed two children (15) __________ signals to each other using a long piece of solid wood and a pin. It was this (16) __________ that inspired his invention of the stethoscope. He later made his first stethoscope using wooden cylinders. He called this instrument “the cylinder”.
