下列有关声音的说法正确的是:[ ]
A.声源处的物体一定在振动
B.声音在真空中也能传播
C.声音不能通过头骨传播
D.声音在不同物质中的传播速度相等
答案:A
If you sit near _____ front of the bus, you’ll have _____ better view of the rapidly changing city.
A./; the
B./; a
C.the; a
D.the; the
简述颌面部软组织损伤清创术.