Count and Noncount Nouns

Gerunds and infinitives are both verbal forms that act as nouns. Gerunds end in -ing, such as swimming, walking, or laughing. Infinitives are the basic verb form with the particle to, as in to swim, to walk, or to laugh. Sometimes it can be difficult to know whether it's best to use a gerund or an infinitive in a sentence. Here are a few rules:

Both gerunds and infinitives can follow a verb, as in, "I don’t like losing," or, "I don’t like to lose." They can also both be the subject of a sentence, as in, "Catching a speeding ball is hard," or, "To catch a speeding ball is hard."

But only gerunds follow prepositions. For example, it’s correct to say, "I can’t leave a painting without finishing it," but it’s not correct to say, "I can’t leave a painting without to finish it."