(located) at; (to be) in; to exist; in the middle of doing sth; (indicating an action in progress)[cedict]
参加
cān jiāㄘㄢ ㄐㄧㄚ
to participate; to take part; to join[cedict]
关于
guān yúㄍㄨㄢ ㄩˊ
pertaining to; concerning; regarding; with regards to; about; a matter of[cedict]
地球
dì qiúㄉㄧˋ ㄑㄧㄡˊ
the Earth; planet[cedict]
的
deㄉㄜ˙
díㄉㄧˊ
dìㄉㄧˋ
of; structural particle: used before a noun, linking it to preceding possessive or descriptive attributive[cedict]
really and truly[cedict]
aim; clear[cedict]
讨论会
tǎo lùn huìㄊㄠˇ ㄌㄨㄣˋ ㄏㄨㄟˋ
symposium; discussion forum[cedict]
上
shàngㄕㄤˋ
on; on top; upon; first (of two parts); previous or last (week etc); upper; higher; above; previous; to climb; to go into; above; to go up; to attend (class or university); third tone of putonghua[cedict]