There is one mistake in each sentence

There is one mistake in each sentence. Find out and correct it

1. As soon as he will come back from his office, tell him to see me.

                                   A                   B                     C               D

2. He regretted not  say goodbye to his girlfriend at the airport.

                           A    B                  C                       D

3. The storm we visited was  a four –days journey from our hotel, so we took the train

                                        A                     B                                                   C

instead of the bus.

                     D

4. Our new neighbours had been living in Paris since ten years before moving to their

           A                                       B                         C                             D

present house.

5. The explanation that our teacher gave us was difficult than the one you gave us.

                                        A                 B                    C                                  D