Time Zones Our planet,the Earth,is the 3rd planet from th...[作者空间]

Listening An unusual day Kathy usually gets up at 6:30, b...[作者空间]

Listening Height And Weight Here are four people. Two of ...[作者空间]

Paul wants to help reduce（降低） pollution and smog（烟雾）. He ...[作者空间]

Paul is a very successful businessman. He owns several re...[作者空间]

Airplantes are the fastest way to travel a long distance....[作者空间]

Dan is a pilot. He flies airplanes to all parts of the wo...[作者空间]

Mammals（哺乳类动物） are covered by hair or fur（毛皮）,have a back...[作者空间]

In modern times we humans face changing conditions. For h...[作者空间]

There are many forms（形式） of life on earth ,including huma...[作者空间]