同根派生 英汉例句They are the first cirrus clouds seen on an outer planet.它們是首次在外行星上發現的卷雲。The planet is twice as large as the earth and is the smallest exoplanet ever found.這顆行星的躰積是地球的兩倍，是到目前爲止天文學家發現的躰積最小的太陽系外行星。