3. Adverbs of time usually come before the verb. Examples: frequently, usually, often, never, often, always, seldom, sometimes, etc,
They seldom go on a holiday; She never admitted her fault; She always tell lies.
4. Adverbs come after an auxiliary + Past Participle and the forms of to be
They have never invited me to their wedding party; I have always loved jazz; He was greatly praised for his novel idea; We must frequently study the vocabulary; We don’t honestly know the answer.