它们一定是由稀有材料制成的。

They must be made from a rare material.

youdao

这些墓葬包括大量由外地材料制成的精细搬运物品，表明了被埋葬者的高度政治地位。

These burials included quantities of finely carried items made of nonlocal material, denoting the high political standing of those interred.

youdao

传统上，机器人很硬，由金属和其他刚性材料制成。

Traditionally, robots have been very hard, made of metal and other rigid material.

youdao