Unit 13 The Water Planet教案

(answer to question 1) in estuaries, animals can enjoy all the benefits of the oceans without having to face many of its dangers. tides provide energy for the ecosystems, but estuaries are protected from waves and storms by islands, mud or sand. nutrients from both the land and the ocean arrive in estuaries.
(answer to question 2) it means the degree to which an area is filled with things or people.
(answer to question 3) they absorb nutrients and pollutants from water coming inland sources, thus cleaning our water.
(answer to question 4) because estuaries act as filters(過(guò)濾器), many pollutants end up in them.
(answer to question 5) estuaries provide both recreation and education for human beings. for example, people can fish, swim and have fun on the beach; scientists and students have endless opportunities to study a variety of life in the habitat. estuaries also contribute to the economy through tourism and fishing.
4. finish the following passage with words from the text.
     estuaries are bodies of water along coasts that are ________ (形成) when fresh water from rivers ________ with salt water from the ocean. in estuaries, the fresh river water is blocked from streaming into the open ocean by either surrounding mainland, or islands. this mixing of fresh and salt water _______ a unique environment ______ with life of all kinds -- a zone between the land and sea known as an estuary. the estuary gathers and holds a ______ of life--giving nutrients from the land and from the ocean, forming an ecosystem that contains more creatures than any other ________ on the earth. estuaries are also important for human beings. they protect water quality by ________ pollutants from water coming from inland sources. they are centers for _______(娛樂(lè)) and education. estuaries, in short, are treasures.
(formed, mixes, creates, filled, variety, habitat, absorbing, entertainment)
iii. post-reading discussion
as we learn from this passage, many cities which are built around estuaries, like shanghai, guangzhou, ningbo, shenzhen are very developed. can you explain why?
( they are near yangtze river delta, pearl river delta…)
(convenient transportation, rich resources…)
iv. writing
do you still remember what we learn about the properties of water? in that passage, the writer introduces the chemical structure and several properties of water to us, such as salinity, density, heat capacity. so from this we know when we are explaining what something is or how things happen, it is important that our explanations should be well organized and easy to understand.