CT机房安装空调，主要原因是()

A．病人和工作人员舒适 

B．不设窗户，使射线屏蔽更安全 

C．设备贵重，保护机器 

D．使计算功能正常工作 

E．不开窗户，避免灰尘进入

[A] stamp
[B] zoo
[C] blackboard
[D] train
[E] post office
[F] park
[G] bank

People write things on it chalk.