let sth run its course

例句：

1. 1. Let me know if you need any help.
   如果你需要任何帮助，请告诉我。
2. 2. She let her dog out for a walk.
   她让她的狗出去散步。
3. 3. Let's not let the meeting start late again.
   我们不要再次让会议开始得太晚。