Active and Passive voice L-9, E-I, P-46.

Charles Goodyear​ (a)   (make) the first sneakers in 1917

• made
• are made

Velcro​ (a)   (invent) by George de Mestral. It​ (b)   (use) to fasten two materials together. Many companies​ (c)   (use) Velcro on their clothing products.

• was invented
• is used
• use
• invented
• used

Roy Plunkett​ (a)   (invent) Teflon in 1946. Teflon​ (b)   (apply) to cookware eight years later. Many cooks now​ (c)   (use) non-stick and pans.

• invented
• was applied
• use
• was invented
• apllied
• uses

The microwave oven​ (a)   (invent) by Perry Spencer in 1947. The first microwave ovens​ (b)   (weigh) 750 pounds and​ (c)   (cost) $5,000.

• was invented
• weighed
• cost
• invented
• was weighed
• was cost

Randolph Smith and Kenneth House​ (a)   (develop) the first battery-operated smoke detectors for homes. Today, smoke detectors​ (b)   (require) in homes, schools, and apartment buildings.

• developed
• are required
• are developed
• required

VCRs​ (a)   (introduce) in 1971. They​ (b)   (allow) families to rent movies at video stores. In 1995, many companies​ (c)   (work) together to develop DVD technology. Today, more DVD machines​ (d)   (sell) than VCR players.

• were introduced
• allowed
• worked
• are sold
• introduced
• are allowed
• sold

The pop-top can​ (a)   (develop) by Ermal Fraze. The top and the ring​ (b)   (stay) attached and​ (c)   (negative cause) litter. Before 1973, soda​ (d)   (bottle) in glass bottles. Then, Nathaniel Wyeth​ (e)   (develop) a plastic bottle that could hold carbonated beverages.

• was developed
• stayed
• didn't cause
• was bottled
• developed