A：Hey，Bruce!You seem unhappy．（66） 　　

B：Yes．I've just come back from the zoo．

A：Have you seen your favorite tigers？

B：Yes．（67） 　　

A：Why not？

B：Because they had to stay in cages（笼子） and they were dirty．

A：（68） 　　I think they should go back to forests or mountains．

B：Even worse，a few children threw something at them．

A：That's too bad．（69） 　　

A：（70） 　　Protecting them is protecting ourselves．

B：Of course．I also told them it was our duty to protect animals．

A．	I'm sorry to hear that．
B．	Did you stop them？
C．	But they didn't look well．
D．	When did you go to the zoo？
E．	Didn't you go to the zoo？
F．	How do you like tigers？
G．	You did quite right．