Movement may occur also in direct response to an outside stimulus; thus, a tap on the knee causes a jerk, and a light shone into the eye makes the pupil contract. These involuntary responses are called reflexes.
- in response to [in - riˈspɔns - tu:] prep. 相应，回应
- stimulus [ˈstimjuləs] n.刺激
- tap [tæp] n. 轻打
- jerk [dʒə:k] n. 抽搐
- pupil [ˈpju:pəl] n.瞳孔
- contract [kənˈtrækt] v. 收缩
- reflex [ˈri:fleks] n.反射
