重庆发布春秋假安排：每学年两次每次2-3天，严禁返校即考试

Use 以...为... to describe taking something as the focus, basis, or core; it’s followed by the role or standard you are setting.

Use 不是...而是... to contrast two ideas: first deny the wrong assumption, then state the real situation or intent.

Use 由 to indicate the responsible person or entity for an action, often in passive constructions like “be decided/made by...”.

严禁 + verb phrase expresses that something is strictly forbidden and must not be done.

让 introduces the person affected, and 把 introduces the object, showing what action they are allowed or caused to do.