three-grade system signal

[three-grade system signal]
[three-grade system signal]

中文释义

三级制信号

单词分析

单词结构:

three-grade system signal

字母数:25

记忆提示

🎯 重点记忆:

  • 单词拼写:three-grade system signal
  • 核心含义:三级制信号