—Talking loudly in a library is impolite.
—In fact, we should also  take care not to cough or sneeze loudly in public.

——_______can I get the iPad if I place  an order today ?
——In about  three days, sir.

呼吸时，呼出的二氧化碳产生的部位是（   ）

“螳螂捕蝉，黄雀在后”这一食物链可以准确的表述为（  ）