2. discover (v): to be the first person to find something important.
discoverer (n): someone who is the first person to find something important.
discovery (n): something that has been discovered.

3. invent (v): to design or create something that has never existed before.
inventor (n): someone who designs and makes new things.
invention (n): something that has been designed or created for the first time.

4. Examples: He discovered a new continent.
His discovery was the law of gravity.
The inventor of the electric light bulb is Thomas Edison.

5. the first practical
telephone
the first mechanical computer
the first powerful
telescope
phonograph
powered aircraft

7. electric light bulb,
phonograph,
motion picture camera
powered aircraft
water screw
the first mechanical computer
the first practical telephone
electricity
a powerful telescope,
an improved compass

9. Present Continuous Tense
I am doing an experiment now.
She is using test tubes to observe
different chemical reactions.
They are looking into the sky through a telescope at the moment.
We are making a model wind turbine at present.