It’s difficult to imagine it as an invention. Is it difficult to imagine it as an invention?
Ballpoint pen Car assembly line To clone
diesel digital stereo system dynamite
electric cell helicopter improvement
instant coffee laser manufacturer
match to patent penicillin
to perfect photocopier to pioneer
satellite Scotch tape steam engine
trainers telescope telegraph
typewriter tyre
Past Simple Passive was were V 3 / V ed
Past Perfect Passive Past Matches had been invented before an incandescence lamp.
A … had been …by the time a … was (were) …. invented, developed, introduced, created, designed A camera had been created by the time a dishwasher was invented.
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