单元：Unit 04.txt

• astronaut
• procedure
• mental
• intelligent
• rocket
• gravity
• frontier
• vehicle
• universe
• determined
• determine
• satellite
• orbit
• giant
• leap
• mankind
• agency
• transmit
• data
• disappointed
• desire
• carry on
• ongoing
• on board
• independently
• independent
• spacecraft
• spacewalk
• jade
• dock
• signal
• recycle
• muscle
• lack
• float
• otherwise
• beyond
• solar
• solar system
• current
• figure out
• sufficient
• soap
• towel
• microwave
• tissue
• facility
• keen
• globe
• argue
• argument
• fatal
• shallow
• result in
• pattern
• analysis
• as a result
• high- end
• monitor
• regularly
• regular
• foam
• pillow
• smartphone
• resource
• closing
• in closing
• mystery
• run out
• attach
• oxygen