* "Boast about something": This is the most common usage, where "boast" is followed by the preposition "about" and the thing being boasted about. For example, "He boasted about his new car."
* "Boast of something": This is another common usage, where "boast" is followed by the preposition "of" and the thing being boasted about. For example, "She boasted of her incredible cooking skills."
* "Boast to someone": This usage implies that the boasting is directed at a specific person. For example, "He boasted to his friends about his recent promotion."
It's important to note that "boast" is often used as a verb and not a noun, so the preposition would apply to the verb and not the word itself.