VOA慢速英语:联合国和欧洲机构计划清理太空垃圾

frequently –adv. happening often

infrastructure –n. the basic equipment and structures such as roads and bridges that are needed for a country, region, or organization to function properly

sector –n. an area of an economy; a part of an economy that includes certain kinds of jobs

entities –n. something that exists by itself : something that is separate from other things

awareness –n. the knowledge and understanding of what is happening in the world or around you