pipe cross section

例句：

1. 1. The engineer used a pipe to connect the two pieces of equipment.
   工程师用一根管子把两件设备连接起来。
2. 2. The scientist poured water through a pipe to test its flow rate.
   科学家通过一根管子往里倒水来测试它的流速。
3. 3. The plumber replaced the worn-out pipe with a new one.
   水管工用一根新的管子替换了磨损的管子。