41.   If your child is having social problems, you need to investigate the cause.

42.   Kielar said Tishman had also hired an engineering firm to investigate the cause of the accident.

43.   Lichtinger said the commission may bring U.S. and Canadian pollution experts to investigate the cause of the bird deaths.

44.   Ms. Anders said several government agencies, including the National Transportation Safety Board, were investigating the cause of the accident.

45.   Nor have they investigated the cause of those spills.

46.   Officials are still investigating the cause of the glitch, which controllers say resembles many others in recent months.

47.   Officials said they were still investigating the cause of the crash, the first loss of life since search operations began.

48.   Only Thursday was a naval conference called in Severomorsk to investigate the cause of the accident.