— Ann is in hospital.

— Oh, really? I ______ know. I ______ go and visit her.

A．didn't, am going to

B．don't, would

C．don't, will

D．didn't, will

下列哪一选项不是蜂窝夹层结构的优点？（）

A、具有较大的弯曲刚度和弯曲强度

B、具有较好的吸声和隔热隔声的性能；具有较高的耐声振疲劳性能

C、具有光滑的气动外形，气密性较好

D、抗湿热环境的能力好