a gradual change in the population structure人口结构的逐步变化

The process is gradual and not without setbacks.这个过程是循序渐进的, 而且不无挫折。

Losing weight is a slow, gradual process.减肥是一个缓慢渐进的过程。

He splashed through the ford and began to climb the gradual slope beyond.他哗啦哗啦地蹚过浅滩, 然后开始爬上那头的缓坡。