Paul wants to help reduce（降低） pollution and smog（烟雾）. He would like to b...

Paul is a very successful businessman. He owns several restaurants. All ...

Airplantes are the fastest way to travel a long distance. Airplant trave...

Dan is a pilot. He flies airplanes to all parts of the world. This was h...

Mammals（哺乳类动物） are covered by hair or fur（毛皮）,have a backbone（脊椎） and ar...

In modern times we humans face changing conditions. For humans to live,w...

There are many forms（形式） of life on earth ,including human beings.myg Li...