VOA慢速英语:研究人员估计了冰河时期地球的温度

calculate – v. to discover an amount or number using mathematics

constrain – v. to control something by limiting it

mammal – n. an animal that feeds its babies on milk from its body

corridor – n. a passageway between two points

allow – v. to permit

species – n. a group of animals or plants that are similar and can produce young animals or plants