Perfluoroallene
[化] 全氟丙二烯
🗣️ 情景例句
What's your problem, Mike?
你现在问题在哪 ，Mike？
The builders are already making plans.
建筑家们已经在着手计划了。
but each year, the dogs are still sent out into the snow whenever a traveller is in difficulty.
但每年还要派狗到雪山地里去帮助那些遇到困难的旅游者，