?来上学

如：come here(来这儿)，come to school(来上学)，go there(去那儿)，go to school(去上学)。

?来学校

... cold 冷的，寒冷的：感冒 come to school 来学校 cool 凉爽的，凉快的 ...

?来校

... come around/round （走）过来 come to school 来校 come true 实现 ...