key portions的用法和樣例：
例句
- All glass vacuum tubes are the key component of solar collectors.
全玻璃真空管是太陽(yáng)能集熱器中的關(guān)鍵部分。 - We know that Iraq has embedded key portions of its illicit chemical weapons infrastructure within its legitimate civilian industry.
我們知道伊拉克已將它非法化學(xué)武器基礎設施的關(guān)鍵部分安放在其合法的民用工業(yè)里。
