The teacher took my hand in h____ and said “keep on going never give up” .
如图,以等边三角形ABC的BC边为直径画半圆,分别交AB、AC于点E、D,DF是圆的切线,过点F作BC的垂线交BC于点G.若AF的长为2,则FG的长为( )
根据句意及汉语提示完成句子。