They enjoyed themselves ________ Christmas Eve.

1. A.
   on
2. B.
   in
3. C.
   at
4. D.
   for

They enjoyed themselves ________ all over the world.

1. A.
   travel
2. B.
   travelling
3. C.
   to travel
4. D.
   travelled

They enjoyed themselves in the park. (改为同义句)

They　_________ ________ ________ ________ in the park.

They enjoyed themselves at the party very much. （改为否定句）