单选题：根据下面资料，回答题 As a boy I dreamed of flying airplanes。 ____ 21 _

根据下面资料，回答题
As a boy I dreamed of flying airplanes。 ____ 21 ___ I told Dad I wanted to be a pilot , he
said,"You need to do your job well on the farm first, and____ 22 ___you may reahze your
dream, "The farm was an everyday responsibility (职责)--that____ 23 ___Saturday, Sunday and
Christmas too, Every morning I got up at four o'clock to milk and____ 24___the cows ．After the milk was bottled ,my older brothers and I____ 25 ___it to people's homes．I was paid five cents a bottle At that time I____ 26 ___that to be successful you have to take care of your responsibilities.
When I was 16 I signed up for flying lessons．To pay for the lessons I____ 27 ___a small restaurant with some friends．One of our regular____ 28 ___ was the president of the Farmers Bank．Every' ____ 29___
I got , I talked to him about my dream One day I told him 1 ____30 ___ $ 3500 to buy my own ___ 31___.He lent me the money so that I could fly people within 150 miles of the airport
Twelve years later I was flying people around the world ____ 32 ___a pilot of a big airline company．After ten years in the comoany I started my own ____33 ___Today I run a billion - dollar company,but it was on the farm that I learned the principles(原则) that have____ 34 ___ me．hard
work and determination do ____ 35 __dreams come true.
第（21）题选 A．When
B．Though
C．Before
D．Since