Experts have found that the disease will lead to a greater increase in the number of sufferers unless ________ seriously when the symptom first appears.
Many clothing manufacturers now substitute artificial silk _____ natural silk to cut down costs of production.
--- Where are you, Nancy? --- Here in the sitting room, _______ to Professor Smith.
Canada is a country ______ many different nationalities as well as one with foreign immigrants ______ the majority of its population.
--- Mum, I’ve at last passed the final exam. --- ________
What _______ great fun it is to play ______ game of basketball after a whole day of study!