----Four dollars a pair? I think it’s a bit too much.

----If you buy three pairs, the price for each will_____to three fifty.

A．come down

B．take down

C．turn over

D．go over

选购主板时要考虑的主要因素是（）

A.稳定性和功能

B.功率和功能

C.稳定性和功率

D.芯片组和功能