阅读下面材料，在空白处填人适当的内容（1个单词）或括号内单词的正确形式。
Qixi is an important festival that celebrates love and ____(devote), which falls on the seventh day of the seventh lunar month of the Chinese calendar. The love story of Niulang and Zhinu, and the Qixi Festival have been handed down for generations. ____ actually these ancient traditions and customs ____(die) out nowadays.
Many a Chinese, particularly youngsters, ____(seem) to know more about St Valentine's Day on February 14th, ____people celebrate it with bouquets of roses, chocolates and romantic candlelight dinners.____(refer) to as the “Chinese Valentine's Day,” Qixi, as a traditional Chinese festival, is more similar ____ a western festival since fewer people than ever will gaze at the heavens to pick out the two stars shining bright on either side of the Milky Way. There are reminders dotted about, in ____form of big ads saying “Sales on Chinese Valentine's Day!” in shops, hotels and restaurants. However, ____(differ) from traditional practices, few young women will mark the festival with their boyfriends, or take part in traditional activities to celebrate ____.
，则乙炔的化学式是（ ）