| Active Voice | |
| Present | |
| Simple | Progressive |
| selling | —— |
| Perfect | |
| having sold | having been selling |
| Passive Voice | |
| Present | |
| being sold | —— |
| Perfect | |
| having been sold | —— |
The participle frequently introduces a phrase. Usually the phrase is used like an adjective; occasionally it is used like a noun (sometimes called the gerund phrase).
Adjective: Seeing your perplexity, I'll offer a suggestion. (Notice the punctuation.)
Noun(Gerund): Playing tennis is good exercise.
The Infinitive
The infinitive is distinguished by the word to, either expressed or understood. The tenses and voices of the infinitive are as follows:
| Active Voice | |
| Present | |
| Simple | Progressive |
| to sell | to be selling |
| Perfect | |
| to have sold | to have been selling |
| Passive Voice | |
| Present | |
| to be sold | —— |
| Perfect | |
| to have been sold | —— |
The infinitive is often used to introduce a phrase; as,
Noun: To get to the top of the hill was a difficult matter.
Adverb: I went to buy the sugar.
Adjective: It's a drawing to be proud of.
Grouping all the facts that we have thus far learned about phrases, and expressing them in diagram form, we have the following: