substitute

n. 代替者,代用品
v. 代替
vi. (for)代替
vt. 用...代替,代以

We substituted a red ball for blue to see if the baby would notice.

我们用红皮球换下了蓝皮球，看这婴儿会不会发觉。

Water is not a proper substitute for wine.

水不是酒的适当代用品。