--Have you seen the movie Qian Xuesen ? --Yes , I am deeply _____by the old great scientist.

--When _____ the abacus _____?   -- In the sixth century by the Chinese people.

In the past the children were made ______15 hours a day.

－ 80% of our work ______ finished. － Really? It’s ______ hard work, you know.

People should __________ from __________ down the trees to protect the earth.