单项选择题
According to the passage, plants on the tundra grow in the ground （）
A．to avoid being eaten by arctic animals B．because fertilizer is not readily available C．to minimize exposure to the cold D．because unfrozen water supplies are very scarce
单项选择题 The author believes that sporting activities.（）
单项选择题 Designers and big stores always make money （）
单项选择题 The first paragraph tells us that the author （）
