Yǔnshí zhuàngjī zài dìmiàn liúxià le yí gè dà āokēng.
The meteor impact left a large crater on the ground.
Tips
memory
凹 is one of those rare characters whose shape literally is its meaning, look at it: it's a notch carved out. Pair with 凸 ('protruding,' shape pushes outward) for the matched set.
