单项选择题
When you post a letter, you must buy （）.
A．a ten-fen stamp B．a new stamp C．a twenty-fen stamp D．a stamp worth 10 fen or more
单项选择题 Why is it useful to carry enough 25-cent coins with you （）
单项选择题 We may conclude that （）.
填空题 A．national B．made C．capital D．annual
