人们更喜欢坚固的家具，因为它可以使用好几代人。

People prefer ___solid furniture because it lasts for generations.

安全测试显示，这辆车的框架异常坚固。

Safety tests showed the car's frame was remarkably ___solid.

尽管使用了几个世纪，这座古老的石桥仍然很坚固。

The ancient stone bridge remains ___solid despite centuries of use.