VOA慢速英语:Very Large Crack Creating Iceberg in Antarctica

crack – n. a line in the surface of something that is broken but not separated into pieces

obvious – adj. easy to see or notice

initially – adv. occurring at the beginning of something

phenomenon – n. something that can be observed and studied that is unusual or difficult to understand or explain fully

ratchet – v. to increase or decrease something by a series of small amounts

vulnerable – adj. easily hurt or harmed physically, mentally or emotionally