Most computer systems are (26) to two different groups of attacks: Insider attacks and outsider attacks. A system that is known to be (27) to an outsider attack by preventing (28) from outside can still be vulnerable to the insider attacks accomplished by abusive usage of (29) users. Detecting such abusive usage as well as attacks by outsides not only provides information on damage assessment, but also helps to prevent future attacks. These attacks are usually (30) by tools referred to as Intrusion Detection Systems.

A．searched

B．checked

C．tested

D．detected

（6分）0.2mol有机物A和0.5molO₂在密闭容器中燃烧后的产物为CO₂、CO和H₂O。产物经过浓H₂SO₄后，质量增加10.8g;再通过灼热的CuO充分反应后，固体质量减轻3.2g;最后气体再通过碱石灰被完全吸收，质量增加17.6g。

（1）试推断该有机物的化学式。

（2）若0.2mol该有机物恰好与4.6g金属钠完全反应，试确定A的结构简式。

（3）试写出A的不与金属钠反应的同分异构体。