You can organize a guessing game or competition. Explain to them how to start guessing, and then do some simple crossword puzzles, so that they can guess the answer after thinking, so that they are interested. At the same time, they can explain the word and its constituent words to students according to riddles, and they can also make sentences with words they can think of to cultivate their divergent thinking. According to the situation, you can add some difficulty to the idioms learned in primary school. If someone guesses correctly, you can also ask him to tell this idiom story, which will not only deepen your memory, but also cultivate your ability to tell stories and write compositions. If he can't say it, you can help him tell the origin and application of this idiom. If it is a competition form, it can also be carried out in groups, and it can be carried out simultaneously in various ways, such as rushing to answer and rushing to answer. Finally, you can judge individual rankings, group rankings and so on. Of course, you have to prepare the prize first. Children like to be praised, especially if others don't guess, and he guesses first, he will be very positive. I'll give you an idea. Prepare the specific content yourself.

I hope this helps.