An adverb of frequency goes before a main verb
(except with To Be)
subject
+
adverb
+
main verb
I always run in the park
He sometimes studies in the evening
An adverb of frecuency goes after the verb “To Be”
subject
+
to be
+
adverb
You are usually very busy at 2:00 p.m.
She is never very sleepy at night
We can also use the following adverbs at the start of a sentence:
Usually, normally, often, sometimes
Often, I like to eat Thai food
BUT we cannot use the following at the beginning of a sentence:
Always, hardly, never