Sarah the seagull（海鸥） and her mom lived in New York by the sea．

Every day Sarah and her mom would fly over the waves， diving in to eat the small fish that swam in the shallow（浅的） water． Sometimes people would feed Sarah and her mother a sandwich or some potato chips． They always had a lot to eat． At night， Sarah and her mother would rest under the roof（屋顶） of a nearby building． It was a quite warm place to live in．

But one day it started to get colder． The little fish that were always swimming in the waves were a lot harder to find． There were no more people coming to the beach， so no one was there to feed Sarah and her mother any sandwiches or chips．

"It is time to fly south for the winter，" said Sarah's mom． "Why？" asked Sarah． "Because it has got too cold here，" explained Sarah's mom． "There is no food， and it will soon get even colder．" "   ▲ ，"said Sarah． "Don't worry，" said Sarah's mom． "We will come back when it is warm again． We are birds． We can change where we live and still be happy． We can have more than one home．"

So Sarah and her mom said goodbye to the beach and flew away． They flew and flew， until they were out of the cold and back into the warm weather． They flew all the way to Miami， Florida．

There， they found a new beach． It was filled with fish， and there were lots of people to give them sandwiches and chips． Sarah's mom even found a new roof for them to sleep under．

"I like this other home，" said Sarah． "It is warm， and we have food． This is a nice place too．"

"I told you it would be nice，" said Sarah's mom． "And when it gets warmer in New York again， we will go back． That is the nice part about being a bird． We can fly to new places whenever we want．"

38． Sarah's mother decided to fly south mainly because of 　　．

A． weather

B． interest

C． sights

D． dreams

39． Which of the following is the best to fill in the blank "   ▲ " in Para 4？　　

A． But it's too late

B． But I like a new home

C． But this is our home

D． But it's too tiring

40． From the passage we can learn that the mother seagull is 　　．

A． strict

B． wise

C． crazy

D． polite

41． We can learn from the story that 　　．

A． people should be friendly to birds

B． mothers like moving here and there

C． the environment is becoming worse

D． a change may help to live better