TOPIC: Usage of preposition after arrive

Usually, we use a preposition 'at' or 'in' after the verb 'arrive' eg, arrive at 7:pm or arrive in USA. However, can we omit the preposition if there is no object after the verb 'arrive'?

You asked whether we can omit the preposition if there is no object after the verb 'arrive'.
Yes, you're correct. We DO use a preposition after arrive as in “arrive at 7 p.m.” or “arrive in the U.S.”, but if there is no time or place following, we don't need a preposition, as in:
“When did you arrive?”
“The train arrived late.”
“My friend arrives (on) Monday.”