单项选择题
Heart （） is much more common these days than it was even ten years ago.
A. surgery B. surgeon C. work D. circulation
单项选择题 We should not let anyone lead us by the （） in our actions. We should always take the initiative in our own hands.
单项选择题 The rodent, （）the mouse, rat, guinea pig, and porcupine, are mammals with incisor-like teeth in both jaws.
