Aside from the basic form of infinitives (to+base verb), they also come in progressive, perfect, and passive forms. |
1. Progressive/Continuous Infinitive |
Form: (to) be + -ing |
Meaning: As it's name suggests, the progressive or continuous infinitive expresses an action or event in progress or happening at the time of speaking. |
Examples: You must be joking. I'll be heading to New York around this time next month. At that time, Keshia was confirmed to be staying with her aunt. |
2. Perfect Infinitive |
Form: (to) have + past participle |
Meaning: The perfect infinitive refers to a time in the past before that of the preceding verb. |
Examples: I'm glad to have worked at that company. Paul must have forgotten about the deadline. Nick was assumed to have checked out the day before. |
3. Passive Infinitive |
Form: (to) be + past participle |
Meaning: Functions similarly to other passive forms. When used after a noun or be, active and passive connote the same meaning. |
Examples: This meat has to be cooked. These gates should be shut always. I am expecting to be offered a promotion. |
4. Combinations |
Perfect progressive + perfect passive infinitives are usual. |
Examples: You must have been tired working all night. Jimmy would like to have presented the flowers to the queen. |
Progressive/Continuous passive infinitives though acceptable are uncommon. |
Examples: He'd like to be being cheered on every time. Mr. Yoshi like to be being seated near the window. |
Progressive/Continuous perfect passive infinitives are very rare. |
Examples: The tower must have been being put up without any machinery. Bianca must have been being scolded at that time. |
5. Negative Forms |
Form: not + infinitive |
Meaning: To form the negative infinitive, place not before the to- or zero infinitive. |
Examples: He asked me not to be late. Elephants ought not to marry mice. You'd better not smile at the crocodile. |
6. To form |
a. Used before an infinitive Form: to + infinitive Example: He wanted to sleep. |
b. Without to Example: Nancy let Clark answer the phone. |
7. Split infinitive |
Form: to + adverb + infinitive |
Meaning: To form split infinitives, separate "to" and infinitive by inserting adverb between them. |
Examples: He tried to really prove his point. Jack hopes to easily excel in class. |