Long ago, man used to ______ with his hands but now man is used to ______ with machines, and sometimes a robot is used to ___ instead of people.
. While he was investigating ways to improve the telescope, Newton made discovery which completely changed man’s understanding of color.
. The breakdown of the machine brought the work into a mess.
Hangzhou is distinguished its beautiful scenery.
. Don’t let yourself be by a small failure in the experiment Try again.
______________food are needed.