It rains very heavily in this area, which has ______ annual rainfall of 7,000 mm, ______ ideal

environment for forests.[ ]

A. the; an

B. an; 不填

C. an; an

D. 不填; the

胸膜摩擦感可于下列哪个时相触及 ( )

A．吸气早期

B．呼吸两相均可

C．呼气末

D．屏气时

E．咳嗽时