下面四幅昼夜半球图中，有可能表示3月21日的是（　　）

下列说法正确的是（ ）

根据短文理解，从A、B、C、D四个选项中选择最佳填空。

    Hi, my name is Dave. I'm 8 1 old. My birthday is 2 December 12th. I have 3 birthday party every year. Today I have my 4 birthday party. I get some gifts at the party. 5 are very good and I really like them. This 6 T-shirt is from my mother. Green is my 7 color. My mother buys me a pair of green 8, too. My father buys some 9 about history for me, because I like 10 best. I think these books 11 very interesting. My grandparents 12 I like playing basketball, 13 they buy me a basketball. I can 14 it with my friends after class. I'm very happy today.

    15 is your birthday, my friend? Do you have a party, too?

如图所示是几种声音输入到示波器上时显示的波形，其中音调相同的是____；响度相同的是____．