VOA慢速英语:科学家训练老鼠开车他们学到了什么？

button – n. something you press to control a piece of equipment

relax – v. to become happy and comfortable because nothing is worrying you

steer – v. to control the direction of a vehicle

treat – n. a piece of free food, drink, etc., provided to someone

flexible – adj. able to be easily changed

enrich – v. to improve the quality of something by adding something to it

hormone – n. one of several chemicals produced in the body that influence growth and development

stress – n. feelings or worry or nervousness caused by difficult situations or problems

task – n. a piece of work, especially something unpleasant or difficult