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 Which of the following statements is not true（）
单项选择题 We may conclude that（）
单项选择题 Of all the oceans in the world, the Indian Ocean contains more than （）
