--- What were you so _____ ? ---My son’s not passing the college entrance examination _______ me most.
Experts say ________ to sunlight for too much time will do harm to one’s skin.
—What about the student in your class, Mr. Wang? —The doctor said that sleep caused him poor memory and poor concentration.
Before driving into the city, you are required to get your car ____.
To avoid on how to use the word, you’d better refer to a dictionary.
Some insects________the colour of their surroundings to protect themselves.