Certain adverbs must be placed right next to the verb they are modifying. Tom does not ride a bike.
In this sentence, the adverb not gets placed right next to the action verb ride.
Just like the adverb not, the adverbs seldom, rarely, always, and never sit right in front of the verb they modify.
Look at these sentence examples:
Tom seldom rides a bike.
Tom rarely rides a bike.
Tom always rides a bike.
Tom never rides a bike.
When you use the adverbs seldom, rarely, always, and never, be sure to place them right in front of the verb they are modifying.