A. When was the last time you went to the zoo?

Maybe when I was in 5th grade.

​=> Corrected : The sentence is corrected grammatically. ​

​(Capitalization)

​(Punctuation) 

B. Yeah!

​=> Another way: Your sentence is okay and this is another way of saying it.​

Hurray! 

Yes Let's go right now.

​=> Another way: Your sentence is okay and this is another way of saying it.​

OK! Let's go!

Our team cheer up!

​​=> Anothoer way: This is another way of saying it.​

Go team!​