It depends. Saying "not know" for less important one, but ..

try to switch the topic that you know. That is more of art and requires practice. 

所有跟帖： 

• less important ones (I mean), but .. -iCall- ♂ (0 bytes) () 10/17/2010 postreply 15:58:13

• 盡其所能做好，老想人家怎麽看是雜念 -iCall- ♂ (0 bytes) () 10/17/2010 postreply 19:33:56