_____ he is very busy, he spends at least two hours every day surfing the Internet in order to find out the latest development in science and technology.
Many countries, for example, Mexico and Japan, _____a lot of earthquakes.
Each of the students, hoping to pass the exam, _____the book.
He told me the news_____, believe it or not, he had earned $1 000 in a single day.
The research is so designed that once _____ nothing can be done to change it.
If _____ carefully, the experiment will be successful.