We had estimated the number of visitors to our school’s hundredth anniversary at about 400, but the __________ number was much higher.

A．actual

B．genuine

C．sincere

D．unbelievable

壁挂式箱体的固定必须采用（），对墙四点固定，箱体安装牢靠、不晃动，无明显歪斜。