Most modern Loran-C receivers，when not tracking properly，have a（n）（）.
A: Bell alarm to warn the user
B: Lighted alarm signal to warn the user
C: Alternate signal keying system
D: View finder for each statio
A: Bell alarm to warn the user
B: Lighted alarm signal to warn the user
C: Alternate signal keying system
D: View finder for each statio
举一反三
- Vervet monkeys use vocal alarm calls to warn each other about the presence of predators.
- Ifthereisafireonboard,informthebridgeandgivethe（）atonce. A: sound B: sounding C: alarm D: signal
- 常见的信号捕获函数是（ ）。 A: kill()和raise () B: alarm ()和pause () C: signal ()和sigaction ()
- 常见的信号捕获函数是（ ）。 A: start ()和 end() B: kill()和raise () C: alarm ()和pause () D: signal ()和sigaction ()
- lighting and signal system