单项选择题
Being closer to the nature has become a favorite __________ for the increasing number of people.
单项选择题 The fear of smallpox, which terrorized the eighteenth century, has no __________ today.
单项选择题 The result of national__________ shows that the population has leveled off owing to the firm family control.
单项选择题 Scientists have made a __________ in their combat against the AIDS.
