key signal

例句：

1. 1. The key signal for success isto stay focused and persistent.
   成功的关键信号是保持专注和坚持不懈。
2. 2. Thecompany's new policyis the key signal for itsfuture development.
   公司的新政策是其未来发展的关键信号。
3. 3. The research team identified thekey signal that would lead to a breakthrough in the field.
   研究团队确定了将导致该领域突破的关键信号。