English Grammar : article, syntax, verbs conjugation, English spelling

Frequency refers to how often something is done. How often something is done can be described with indefinite adverbs and definite noun phrases. The most common indefinite adverbs are: always, usually, often, sometimes, rarely, and never.

Adverb Frequency it represents
always 100 percent of the time (or almost 100%).
usually about 80 percent of the time.
often more than half of the time.
sometimes less than half of the time.
rarely about 20 percent of the time.
never at no time.
“It is always sunny in Southern California.” “People usually go to church on Sunday morning.” “I often watch television on Saturday night.” “Stephen sometimes misses classes in the afternoon.” “There is rarely enough time in a week to get everything done.” “I have never been to Wyoming, but I hear it is a nice place.” The second way to talk about frequency is to use definite noun phrases. These phrases say exactly how often something is done. For example, “three times a day,” “twice a month,” “once a year”: “You should take this medicine three times a day.” “That magazine is published twice a month.” “The committee is scheduled to meet once a year.”