Under the leadership of the teacher, the students went to the street to clean up the small advertise

This statement is incorrect.

Because since it is said that it is the street.

And in the public toilets.

It's repetitive and contradictory in location.

So it should be changed to.

Under the guidance of the teacher, the students went to the streets to clean up the small advertisements.

Public toilets are originally on the street, so the two terms contradict each other; One of them should be removed; It should be: under the guidance of the teacher, the students went to clean up the small advertisements posted on the public toilets.

It should be: the students, under the guidance of the teacher, went to clean up the small advertisements on the walls of the public toilets on the streets.