瓶颈 (píng jǐng): คอของขวด

When this project reached its halfway point, it hit a bottleneck; no matter how hard we tried, progress stalled.

The company's development hit a bottleneck, with sales showing no growth for three consecutive quarters; management decided to explore new markets.

When learning a foreign language, many people encounter a bottleneck at the intermediate stage, feeling that no matter how they study, they make no progress; at this point, they need to change their study methods.

As the urban population continues to grow, traffic congestion has become a bottleneck constraining the city's development.