Thank you very much for your prompt advice to my question.
However, I am stuck with another grammar assignment (see passage below)and hope to get some urgent advice again.
The passage goes like this (now the verb ''STAYED'' in my original passage is changed to the verb ''REMAINED''):
John was a very mischievous boy. One day, he decided to steal some
rambutans from his neighbour's garden. He climbed over the fence to get
into the garden. There, he found a lovely rambutan tree, full of big red
rambutans. He was busy plucking the rambutans when he heard a voice
shouting, ''You thief! Get down!''
John looked down and saw his angry neighbour, Mr Yellow. He remained
______ the tree. Mr Yellow climbed up and brought John down..........
In the above passage, should I fill the blank with ''UP'' or ''ON''.
Thank you very much for your advice!