You have to wear a helmet and a life jacket for protection, just ____ you fall into the water.
When Steven suddenly remembered that he had left his mobile in the office, the train was already ________.
Researchers have found clear and convincing evidence ________ happiness is the key to better health and longer lives.
—Do you think our teachers will free us of homework today? This year’s sports meeting starts tomorrow.—______. After all, we are already Senior 3 students.
Japan’s economy _______ in the past twenty years. No one knows how long it ______ before it regains its increase.
Unlike many other boys of his age who are often addicted to PC games, he is _______ on outdoor activities in the mountains.