Water exists as a solid, a liquid and a gas.

水以固体、液体和气体的形态存在。

solid fuel

固体燃料

The old house has a solid foundation.

这幢旧房子的地基很牢固。

A solid parent-child relationship is often a strong support for teenagers as they face challenges.

父母与子女之间的牢固关系，常常是青少年面临挑战时的强大支撑。

There is solid evidence to show he wasn’t there when the crime took place.

有可靠证据证明案发时他不在现场。

a solid ball

实心球