Exercise 1: Choose the word (a, b, c, or d) that best fits each of the blank spaces.

An American called Thomas Alva Edison (1)___the first man (2)___sound. In 1878, he invented a machine (3)____a phonograph. The phonograph was a bit (4)___a record player, but it used metal cylinders (5)____discs. Flat discs (records) appeared ten years (6)____.

Tape recorders first appeared (7)_____the 1930s, but they were large and expensive. Then, in 1963, the Philips Company developed the first cassette. Cassettes are still very popular all (8)_____the world.

(1)...................

• A. 
  is
• B. 
  was
• C. 
  to be
• D. 
  a & b