She attempts to call for help but her cell phone is unable to get a signal.
她想打电话寻求帮助，但是她的手机在这里接收不到信号。
2
Some people deem it is a dangerous signal and call for public awareness of the negative effects it has brought about.
有些人认为这是一种危险的信号，因此需关注其给社会带来的负面影响。
3
Or, you call some function that was in the middle of the manipulation of the global data structure and you call the same function from the signal handler.