词组搭配
Watchful and prepared for danger, emergency, or opportunity
警戒着，防备着：注意着且防备着危险、意外或机会
bird watchers on the alert for a rare species.看守者人密切注意稀有鸟类
bird watchers on the alert for a rare species.
看守者人密切注意稀有鸟类
