1. 暴跌：financial crisis - 金融危机 | plummeted - 暴跌 | stocks - 股价

2. 大幅下降：Have her platelets dropped?|血小板下降了吗? | Plummeted.|大幅下降 | New labs show they're under 40.|最新读数显示还不到40

3. 垂直落下：at stake: 受影响 | plummeted: 垂直落下 | measured in money values: 不能用钱来衡量的

4. 急剧减少：conservationists 天然资源保护论者 | plummeted 急剧减少 | prompting 促使