With all my attention _____ my homework, I didn't even notice my father standing by me.

A．to fix on

B．fixed on

C．fixing on

D．to be fixed on

开展联合执法检查时，应当按照法定程序进行；但出于实际需要，并经联合执法检查单位领导集体研究同意的，可不按程序进行检查。