the use of signal
举一反三
- You can use the cell phone _____ the signal is strong enough.
- Use _______ at the beginning of the conclusion to signal that you're wrapping up the essay.
- When people use __________ such as a signal to the end, it can make the structure much clearer.
- To signal a pause longer than a comma, or a change in tone, we can use a ______.
- The use of trigonometry(三角学) to describe the electrical signal has proved very valuable for engineers.