Call for help.

Meaning: This means to ask for assistance or support by shouting or making a sound. It's like saying, Make a noise to get someone's attention so they can help you.

Choice of Words: Call means to shout or make a sound to attract attention. For is used to indicate a purpose. Help means assistance or support. The sentence "Call for help" is a command to ask for assistance or support by making a sound or using words.