科学家们发现了保存完好的乳齿象骨骼，揭示了它们的生活习性。

Scientists discovered well-preserved ___mastodon skeletons, revealing details about their way of life.

这台庞大的旧电脑在办公室里就像一只远古巨象，早已跟不上时代。

The huge old computer in the office is like a ___mastodon, completely outdated by modern standards.