21.   But the company warned that full-year earnings will drop as low water levels make it necessary to import power.

22.   But the early pumps were crude, damaging blood cells and making transfusions necessary.

23.   But the Israeli government defends the tactic as a life-saving tactic for Israelis, made necessary by the conflict.

24.   But the convention made it necessary to smooth such things over.

25.   By lying under oath, Clinton made it necessary for the House to consider impeachment.

26.   Central to their vision of the future is a thorough computerization of biology, made necessary by the vast computing power of the genome itself.

27.   Clinton said he is reluctant to agree not to bring up the treaty again next year, since world events might make it necessary to consider it again.

28.   Coin hoarding made this necessary.

29.   Coming competition in the electricity industry makes it necessary to cut costs, the company said.

30.   Denki Rengo says restructuring has made it necessary to set out conditions firms must meet when dismissing employees.