41.   The cultures of the two countries are very different.

42.   The dispute has soured relations between the two countries.

43.   The incident has strained relations between the two countries.

44.   The incident soured relations between the two countries.

45.   The most notable difference between the two countries is a result of legislation.

46.   The mountains form a natural barrier between the two countries.

47.   The peace treaty promises an end to war and opens the borders between the two countries.

48.   The protest event data are coded from a reading of the Monday issues of major newspapers in the four countries.

49.   The river formed a natural boundary between the two countries.

50.   The river forms the border between the two countries.