根据对话内容,在横线处填入正确的单词,补全对话（以下）
Helen,what's this in English?
it's a 71.____.
how do you 72___it?
B-A-S-E-B-A-L-L,beaseball.
is it your baseball?
no,it isn't .my brother likes ppiaying sports .it's73___baseball.
is that your 74.___book?
no,it isn't .look!sandra's75.___is on it .it's her English book.
根据对话内容,在横线处填入正确的单词,补全对话