My watch is not here. Maybe ______ took it. [ ]

A. somebody

B. anybody

C. everybody

D. nobody

某烃经李比希元素分析实验测得碳的质量分数为85．71%，该烃的质谱图显示：分子离子峰的质荷比为

84，该烃的核磁共振氢谱如下图所示。

（1）请确定该烃的实验式、分子式。

（2）若红外光谱表明分子中含有碳碳双键，写出结构简式。