Complete the sentences with this, these, it or they.
a) 《Are ____ keys Tom's?》 《No, ____ aren't》.
b) How much are ____ trousers?
c) 《 ___ book is interesting》. 《No, ____isn't. ____'s boring.
d) I don't like ____ cheese.
e) 《Do you like ____ jacket?》 《 Yes, ____'s fashionable》.