31.   Power is, in any event, a serious problem on the Moon.

32.   Private economists counter that the rosy statistics hide serious problems.

33.   Repudiation of a claim under this clause can cause serious problems.

34.   Rising unemployment is posing serious problems for the administration.

35.   Serious problems from a life onshore can fade rapidly to distant memories as sight of land is lost.

36.   She began to suspect she had a serious problem after an appearance on a Washington television station.

37.   Sleep disorders are a serious psychological problem.

38.   The absence of competition in the command political economy can result in problems as serious as those from excessive competition.

39.   The Coast Guard also has said it has found no serious problems caused by adding the two towers.

40.   The corporation has run into serious financial problems.