Easily confused words



   What are the differences between these pairs of words?

   

   Advice                                                        advise

   Ensure                                               insure

   Envelop                                             envelope

   Formally                                            formerly

   Later                                                 latter

   Passed                                               past

   Perspective                                         prospective

   Precedence                                         precedents

   Prescribe                                            proscribe

   Principal                                            principle

   Stationary                                          stationery

   Practice                                              practise