—Would you mind answering some questions on shopping habits?

— ________.

A．Yes, with great pleasure

B．No, I am afraid I can't make it

C．Yes, it is worth the time

D．No, as long as it doesn't take long

合并下列各式的同类项：

（1）3x-8x-9x；

（2）5a²+2ab-4a²-4ab．