He thought for a long while before finally speaking.
Tips
usage
Colloquial intensifier of 半天 ('half a day' = 'a while'). The 老 prefix means 'really / a whole' — the same emphatic 老 you see in 老远 'really far,' 老早 'long ago.' Often paired with 等了, 想了, 找了 to convey impatience.
