No
No, then is not a preposition. It is a conjuction.Than is a preposition.
At is a preposition. Anything that can be ___ the box is a preposition. For Example: At the box.
If is not a preposition. It is a conjunction.
If a preposition does not have an object, it is not a preposition. It is an adjective, adverb, or possibly a conjunction.
A prepositional phrase begins with a preposition and ends with an object of a preposition.
The lackluster battle was punctuated by sporadic mortar fire.
Shopping without a list may only fulfill sporadic needs. My sporadic shopping helps me to buy in bulk.
to be sporadic and without pattern to be sporadic and without pattern
His aim was sporadic and the bullet holes were scattered randomly.
We huddled in our trenches, listening to sporadic enemy gunfire.
Sporadic means not occurring every time - it's a once-in-a-while change.
sporadically
He came in at 12:00am and said where are my students?
sporadically
Nothing
No, then is not a preposition. It is a conjuction.Than is a preposition.
Bernt Maehlum has written: 'The sporadic E auroral zone' -- subject(s): Auroras, Sporadic E (Ionosphere) 'Small scale structure and drift in the sporadic E layer as observed in the auroral zone' -- subject(s): Auroras, Sporadic E (Ionosphere), Ionospheric radio wave propagation