【明報專訊】"If you look over there in the meadow（ 草地） you will see a rare sight," Elmer said. "Those look like spacemen（ 外空人）! What are they doing there?" Tom exclaimed. "Force of circumstances has caused them to land," Elmer smiled. Force of circumstances refers to a strong internal（內 在 的）or external（外在的）influence requiring someone to do something.