某厂房结构受吊车荷载作用而保持坚固不坏，这体现了结构的()功能.

A.安全性

B.适用性

C.耐久性

D.可靠性

I tried hard to get some information about the new technology out of his mouth, but he remained_________．

A．quiet

B．secret

C．silent

D．calm