The development of industry has been ____gradual process throughout _____ human existence, from stone tools to modern technology.
— Pay you weekly or monthly? — . Either is OK.
by the thunder, the little girl dare not sleep in her bedroom.
It wasn’t until 1970 the war finally came to an end after seven years of hard fighting.
Never in my life such horrible food.
Uncle Li has been working in the factory for more than thirty years, so he deserves .