通常吸入气雾剂的微粒大小以在0.5～5μm范围内最适宜。（）
参考答案：对
--- I will go to Hong Kong to do some sightseeing.---- ________ .
A．No , I won' t .
B．No problem .
C．Have a good time .
D．It is kind of you
心肌收缩有哪些特点？
