单元：Unit 05.txt

• billion
• native
• attitude
• reference
• refer
• refer to
• system
• despite
• ups and downs
• factor
• based
• base
• bone
• shell
• symbol
• carve
• dynasty
• variety
• major
• dialect
• means
• classic
• regard
• character
• calligraphy
• global
• affair
• appreciate
• specific
• CE
• struggle
• tongue
• point of view
• semester
• gas
• petrol
• subway
• apartment
• pants
• beg
• equal
• gap
• demand
• vocabulary
• description
• relate