71.   His challenge to Mrs Thatcher brought her down.

72.   The demonstrators have now made a direct challenge to the authority of the government.

73.   The regional parliament threw down a new challenge to the central authorities by passing a law allowing private ownership of businesses.

74.   Do you accept my challenge to a game of chess?

75.   He took the comment as a challenge to his manhood.

76.   Another challenge to me was not to beat myself up if I ate something that was unhealthy and to take it as a sign to abandon my healthful habits.

77.   A crisis then unfolded involving a challenge to the leadership of Margaret Thatcher.

78.   The Gulf crisis was described as a fundamental challenge to the vision of a peaceful world order which served as an example of the continuing risks of aggression.

79.   Meanwhile, the transitional government continued to face challenges to its authority.