在下列图形中，既是中心对称图形，又是轴对称图形是[ ] A、等腰梯形 B、正三角

Susan: Where are you going, David?
David: To Beijing.
Susan: It's a long trip from here by bike. How long will it take you to 1. c______ it?
David: About two years.
Susan: How many 2. o______ you are making the trip?
David: Five.
Susan: 3. W_______ are you making it?
David: We are trying to collect some money.
Susan: What will the money be used for?
David: To a charity 4. c_______ Protecting the Red-Crowned Crane.
Susan: That sounds great. Good 5.  l_______ with your trip.
David: Thanks.
1._______ 2._______ 3._______ 4._______ 5._______