The computer centre, _______ last year, is very popular among the students in this school. [ ]

A. open      

B. opening    

C. having        

D. opened

吸气时，胸廓、肺容积、肺内气压变化情况是（　　）

A．胸廓扩大，肺容积增大，肺内气压增大

B．胸廓扩大，肺容积增大，肺内气压下降

C．胸廓缩小，肺容积缩小，肺内气压小降

D．胸廓缩小，肺容积缩小，肺内气压增大