Rule 1

A. With action verbs.

The adverb comes immediately before verbs of action, in affirmative, negative or questions, as in examples 1 and 2.

B. With verb To Be (am, is, are).

The frequency adverb comes after the verb to be, in affirmative, negative or questions, as in example 3.

Rule 2

In contrast, frequency phrases (which are composed of more than one word) never come in the middle of the sentence. And it is also possible to use both a frequency adverb and a frequency phrase in the same sentence, as you can see it in the next example:

Rule 3

Now, we will analyze some examples with time expressions.

A. Time expressions signal when the action happens, in the present, in the past or in the future, and they can come at the beginning as in examples 1 and 2.

B. At the end of the sentence as in examples 3 and 4.