△ABC内接于⊙O，若∠A=40°，则∠OBC的度数为（   ）

如图，取两张白纸，让其平行地自然下垂，向两纸中间用力吹气；

阅读下面短文，从方框中选出适当的词，并用其正确的形式填空，使短文意思完整。每词限用一次。

   It’s very important for everyone to protect the environment. As a student, I always try my ____  to save energy at home. I turn off ____  when I don’t need them. And I try to save water when I wash the dishes. I don’t ____  bottles or newspaper away because it’s better to recycle them.
   I think everyday activities at home can make a difference to the environment. I feel proud of ____, and I will not only keep saving energy but also advise others to do the same things as me. If everyone cares about ____  the environment, I’m sure we’ll have a better life.