分子式为C5H12O的醇,其分子中含有两个-CH3、两个-CH2-、一个和一个-OH,则它可能的结构有[ ]
A.5种
B.3种
C.2种
D.4种
答案:D
. — She looks very happy. She __________ have passed the exam.
— I guess so. It’s not difficult after all.
A.should
B.could
C.must
D.might
什么是监控摄像机的自动增益控制(agc)?