生物圈是指 [ ]

A．地球上所有生物的总称    

B．大气圈和水圈的总称  

C．土壤岩石圈的总称    

D．地球上所有生物及其生活领域

Excuse me I _____ I was blocking your way. [ ]

A. didn't realize

B. don't realize

C. haven't realized

D. wasn't realizing