51.   The Chicago Board Options Exchange, the first devoted to options trading, opened just as the Black-Scholes theory was published.

52.   The door opened as Rivera approached, apparently because someone was exiting.

53.   The door to new drilling and exploration on public lands has opened just as the price of energy and natural gas has plummeted.

54.   The exercise opened as President Kim Dae-jung stressed the need for solid military security while pursuing reconciliation with North Korea.

55.   The house where he was born was opened as a historical monument.

56.   The investigation opened as talks continued between bankruptcy administrators and ING of the Netherlands over the sale of the failed British investment firm.

57.   The list of words in the dictionary will open as a Word file.

58.   The house was opened as a museum last year.

59.   The modest row house has been restored to its original state by the National Trust of Britain and opened as a museum.

60.   The restaurant opened exactly as scheduled and other events like lectures and the nightly musical entertainment also began promptly.