VOA慢速英语:Using Head in Soccer May Be Dangerous for Children

collide – v. to hit something or each other with strong force; to crash together or to crash into something

concussion – n. an injury to the brain that is caused by receiving a powerful hit to the head

testament – n. proof or evidence that something exists or is true; informal – compliment, or good result from attention being paid

league – n. a group of sports teams that play against each other

frequently – adj. happening often