when/after she arrived at the school
注:用when还是after要根据上下文判断.
例如:当她到达学校之后,她看见学生们在唱歌.
She saw the students singing when she arrived at the school. (主句的动作是与“到达学校”同时发生或者在当时仍然持续的)
当她到达学校之后,她就直接去找校长.
She went directly to the headmaster after she arrived at the school. (主句的动作是在“到达学校”之后发生的)