生活中常有这样的感觉，当你吃饼干或硬的食物时，如果用手捂着自己的双耳，自己会听到很大的咀嚼声，这说明______能够传声（选填“固体”、“液体”或“气体”）；但是你身旁的同学往往却听不到明显的声音，这是因为______不同，传声效果不同．请根据此现象从物理学的角度提出一个合理的猜想______．

—It is reported that the government has lightened the burden on the students.

—Oh，today we are still _____ from heavy schoolwork，_____ at preparing us for the entrance

examination.[ ]

A. suffering;aiming 

B. suffered;aimed

C. suffering;aimed 

D. suffered;aiming