单项选择题When he got out of the manager's office, from his facial expression we knew that his proposal must have been turned down.
单项选择题The People's Republic of China was founded in 1949.
单项选择题If parents are not careful, children tend to neglect their homework.
单项选择题The doctor explained to the students the hazards of radiation upon human beings.
单项选择题The very north and south regions are covered with ice and snow.