heart beat

例句：

1. 1. She felt her heart beating faster as she walked up the stairs.
   她上楼梯时感觉到自己的心跳加速了。
2. 2. The doctor checked his patient's heart beat to ensure it was normal.
   医生检查了病人的心跳以确保它是正常的。
3. 3. He sat down on the couch and watched his heart beat in time with the music.
   他坐在沙发上，看着音乐的节奏与他的心跳同步。