Under the sea Period 7 Listening Task，Talking and Writing
suppose you were a citizen in a coastal city in china，shark hunt is a serious problem in your province.try to persuade the local government to take action to protect wild life in a polite way with the help of the following expressions：
i don't think it is wise to...
it would be better if we...
it is a good/wise idea to...
i suppose it is right...
i wonder if...
why not...
we'd better...
step 4 homework
write a persuasive letter to the local government to control the improper hunts.
備課資料
1.killer whales
common name：killer whale
scientific name：orcinus orca
size：
females can reach lengths up to 24 feet and weigh between 3000 to 8000 lb.males can reach lengths up to 27 feet and can weigh up to 12 000 lb.calves are about 8 feet long and 300 to 400 pounds at birth.
where are they found?
from the north pole to the south pole from the indian ocean to the atlantic，killer whales are found in all oceans of the world.
what do they eat?
how do they get a name like “killer whale”？killer whales are one of the top predators in the sea.as a group，killer whales are known to eat fish，squid，seals，sea lions，penguins，even other whales.
but，keep in mind，it would be difficult for a killer whale off the coast of california to eat a penguin.killer whales eat the food(or prey)that's available to them.for example，a killer whale that lives in the northern pacific can hunt harbor seals，california sea lions，and a variety of fish.a killer whale in the antarctic could find weddell seals，leopard seals，and penguins!
researchers studying killer whales in the northwest pacific have found that some pods feed primarily on fish and others seem to prefer marine mammals.
a killer whale uses its sharp teeth to catch its prey.
killer whale highlights：
scientists have determined that killer whales can live a maximum of 35 years.how？by looking at a cross－section of a killer whale's tooth.killer whales，like other marine mammals，produce a periodic growth layer on the teeth.by counting these layers，scientists can estimate the animal's age.
you can tell an adult male from an adult female by the shape of their dorsal fin.this is a male(photo below)，how do we know？a male's fin is very tall(up to 6 feet tall)and triangular shaped.a female is shorter(3 feet)and curves back toward the dorsal fin(see the picture of the mother/calf above).
2.the earth's oceans can reach depths of up to 11 000 meters.that is deep enough to cover mt.qomolangma！the oceans are incredibly large and contain several different habitats.to make it easier to describe the various parts of the oceans，marine scientists usually divide the oceans into five zones.each zone is different mainly as a result of how much sunlight reaches it.