Strange things happen to time when

Strange things happen to time when you travel, because the earth is divided into twenty-four parts, ___1___ a part. You can have days with more or fewer than twenty-four hours, and weeks with more or fewer than seven days.Your ship goes into ___2___ time part every day if you make a five-day journey across the Atlantic Ocean. As you go into each part, the time ___3___ one hour. Traveling west, you set your clock back; traveling east, you let it ahead. Each day of your journey has either twenty-five or twenty-three hours.If you travel by ship across the Pacific, you ___4___ the International Date Line. This is the point where a new day ___5___. When you go across the line, you change your calendar one full day, back or ahead.