李师傅加工一批零件共用了15小时，平均每小时加工零件48个，这批零件有多少个？
48×15=720（个）．
答：这批零件有720个．
Everyone can play an important part in society. As members, we should try our best to do __ .
A. how we should do B. what should we do
C what we should do D. how should we do
患者，气短。查体：气管向左偏移，右侧胸廓饱满，叩诊出现实音。应首先考虑的是（）
A．右侧胸腔积液
B．右侧气胸
C．肺气肿
D．右侧胸膜增厚
E．右侧肺不张
