1.freshwater lake淡水湖,  saltwater lake咸水湖,  Caspian Sea里海,  Superior lake苏必利尔湖,  Baikal Lake贝加尔湖,  Nile尼罗河,  Amazon River亚马孙河,  Chang Jiang River长江,  deep深-deeper更深-deepest最深. 

2.Did you go anywhere on summer vacation? 你暑假去什么地方了吗?

   I went to ………. 我去了..........

   I went to Russia.

   Did you see anything special? 你看到什么特别的吗?

   I saw ………, …….. is ………... 我看到了..........., ……..是……….

   I saw Caspian Sea, Caspian Sea is the biggest lake in the world.

   I saw Baikal Lake, Baikal Lake is the deepest lake in the world.

   I saw Nile, Nile is the longest river in the world.

3.Caspian Sea is bigger than Superior Lake.

   Superior Lake is bigger than Baikal Lake.

   Caspian Sea is the biggest salt water lake in the world.

   Superior Lake is the biggest fresh water lake in the world.

   Caspian Sea is the biggest lake in the world.

   Baikal Lake is deeper than Caspian Sea.

   Caspian Sea is deeper than Superior Lake.

   Caspian Sea is the deepest saltwater lake in the world.

   Baikal Lake is the deepest freshwater lake in the world.

   Baikal Lake is the deepest lake in the world.

   Nile is longer than Amazon River.

   Amazon River is longer than Chang Jiang River.

   Nile is the longest river in the world.

   Amazon River is the second longest river in the world.

   Chang Jiang River is the third longest river in the world.

4.比较级:

   ……………. is ……….. than ……….. ……….比………更………

   Stace is taller than Jimmy.

   The bear is fatter than the monkey.

   Watermelon is sweeter than blueberry.

   The peacock is more beautiful than the snake.

   Action movie is more exciting than documentary.

   Beef steak is better than fish steak.

   最高级: 

   ………. is the ……… ........是最...........

   Yao Ming is the tallest.

   Lion is the strongest animal.

   Watermelon is the sweetest fruit.

   The peacock is the most beautiful animal in the world.

   Rush Hour is the best movie.

   This is the most educational documentary.