Inflate your life jacket by pulling sharply on the cord.猛拽绳扣使你的救生衣充气。When it returns to shore, the life-jacket will deflate and revert to a harness.返回岸上后，救生衣就会瘪掉，恢复成背带状。The life jacket buoyed her up until help arrived.救生...
Between these ocean - filled valleys, there are wooden peninsulas and islands.海水灌满的山谷中间, 有许多树木葱茏的半岛和岛屿....erosion of the river valleys.河谷的侵蚀Glaciers gouged out valleys from the hills.冰川把丘陵地带冲出一条条山谷.Farmers worked the fer...
他们群集在老师的周围.They trooped around the teacher.囚犯群集在围墙里.The prisoners horded together in the compound.特定的群集度是多数植物特有的特征.A certain sociability degree is a specific character of most plants....