As the busiest woman in the village, she made _____ her duty to look after all the other people’s affairs in that village.
People should be cautious ______their personal information when surfing the Internet so as to prevent certain computer viruses ______ it.
The local police were______ by their authorities to _____ the situation as soon as possible.
Only when people have enough to eat and plenty to wear _______ to talk about environmental protection.
Through thorough investigation, Dr. John Snow was finally able to prove that the outbreak of Cholera _____ people’s drinking of polluted water.
By careful observation and precise calculation, Nicolaus Copernicus _____ that there is no one center in the universe and the sun is the center of the solar system.