Strange things happen when you travel, because the earth is divided into twenty-four zones （时区）．The time difference between two zones is one hour．You can have days with more than twenty-four hours and days with fewer than twenty- four hours．You can have weeks with more than seven days and weeks with fewer than seven days．
If you make a five-day trip （旅行） across the Atlantic Ocean （大西洋） , your ship come into a different time zone every day．As you come into each zone, the time changes one hour．If you travel west, you set your watch back．If you travel east, you set it ahead （向前）．Each day of your trip has either twenty-five or twenty-three hours．
If you make a trip by ship across the Pacific Ocean （太平洋） , you cross the International Date Line（国际日期变更线）．This is the point where a new day begins when you cross the line, you change one full day．If you travel east, today becomes yesterday, if you travel west it is tomorrow．
Something interesting will happen to the time if you travel because_____．

A．a day has always fewer than twenty-four hours

B．a day has always more than twenty- four hours

C．a day has more or f ewer than twenty-four hours

D．some time zones are large and some time zones are small

The time difference between two time zones is_______．

A．twenty-four hours	B．one hour
C．two hours	D．twenty-three hours

If we crossthe Atlantic Ocean, we_______．

A．change one full day

B．set our watch back

C．set our watch ahead

D．set our watch back or ahead

If we travel east across the International Date Line on July 5th, the date becomes July______．

A．3rd

B．4th

C．5th

D．6th

The Atlantic Ocean________．

A．is in one time zone

B．is divided into twenty-four zones

C．is divided into five time zones

D．can not be crossed in five days