The need for an operation，especially an immediate operation， almost always comes as a ______ to the patient and his family. 

---- The reason why he has been such a success is ________he had lost his money.

Before choosing a career you should spend time thinking about your personal______and weak points.

Pine trees, of which there are almost one hundred ____, are found throughout the North Temperate Zone.

To our excitement，two ______ of students ______ a success after three years' hard work.