Present and past participle

A clause with an active verb form can be shortened to a modifying phrase by replacing that + verb with the present participle verb form verb+ing.

A clause with a passive verb form can be shortened to a modifying phrase by replacing that + verb with the past participle verb form verb+ed.

The forms –ing and –ed can be used:

·         Combined with other words to make participle clauses.

·         After nouns to make reduced relative clauses.

·         After conjunctions and prepositions.

Here, there are some examples:

Anyone who makes too much noise can be asked to leave.

Anyone making too much noise can be asked to leave.

After they had closed all the windows they turn the heater on.

After closing all the windows they turn the heater on.

When you ski you should keep your knees bent.

When skiing you should keep your knees bent.