N. 1 mark it.

2。 Signs and billboards

3。 Sign language

There is no sign of rain. There is no sign of rain.

Verb (abbreviation of verb) signature = > signature. Noun (short for noun)

signal

Countable signals (usually modern electronic signals, including traffic lights)

Send a signal to sb.

There is a similar one.

sigh

sigh

This is my own high school notes, I hope it will be useful to you.

They are just appearances.

The meaning is actually very clear. You have made it very clear.

There will be no problem in doing the problem.

There is no fixed collocation, but I gave you a list of phrases ~