It is said that bad living habits as well as dirty surroundings, stuffy rooms and some other factors ________ the wide spread of H1N1.
My boss insisted that I _______ the work before ten o’clock tonight.
The country has _______ great changes and become a developed one.
We are often _____ by the doctors to eat more healthy food and take plenty of physical exercise.
We asked the teacher to explain _______.
—Did you see a man in black pass by just now? —No, sir. I ______ a newspaper.