这句话里的twisting
问题描述：
这句话里的twisting
Medium-sized ocean vessels can sometimes reach there,but the twisting course and shifting sandbars can make this transit difficult.
这句话里的twisting course和shifting sandbars是什么意思?
答
twisting course 弯弯曲曲的河道
shifting sandbars 移动的沙洲