钙基脂是一种润滑脂，有较强的机油性，使用温度不宜超过100℃。
参考答案：错
— Look, what an old palace! It looks so great!
— Yeah, it ______ nearly 800 years ago. [ ]
A. was building
B. was built
C. has built
D. is built
某台变压器,油量为20t,第一次取样进行色谱分析,乙炔含量为2.0μL/L,相隔24h后又取样分析，乙炔为3.5μL/L。求此变压器 乙炔含量的绝对产气速率？（油品的密度为0.85g/cm3）
