Some action words join with a little word like on, up or out. Together the words make a new meaning.

put on means to organise (a show). dress up means to wear special clothes. Keep the two words together: say put on, not only put.

✦ "The school put on a play in May."

✦ "The actors dress up in bright clothes on stage."

Some phrases have nothing after them. In the past, only the first word changes.

We say sold out, turned up and warmed up. Do not add -ed to the little word: not outed, not upped.

✦ "The dancers turned up early and warmed up in the hall."

✦ "The circus tickets sold out very fast."

take part in always needs in. After in, say the name of the event.

Say take part in a show. Do not leave out in: not "take part a show".

✦ "Six children took part in the circus show."

✦ "Many dancers took part in the ballet show."

look forward to means we feel happy about something that will come. After to, say a name of a thing or a word that ends in -ing.

Say looking forward to seeing. Do not say "look forward to see".

✦ "I am looking forward to seeing the ballet on Saturday."

✦ "The children look forward to the magic show."