pulse sharpening

例句：

1. 1. He was having a hard time keeping his pulse under control.
   他很难控制自己的脉搏。
2. 2. The doctor checked her pulse to make sure she wasn't in shock.
   医生检查了她的脉搏，确保她没有休克。
3. 3. She felt the rapid beating of her heart as she ran.
   她感到心脏的快速跳动，当她跑步时。