More probable is bird transport,either externally,by accidental attachment of the seeds to feathers,or internally,by the swallowing of fruit and subsequent　excretion of the seeds.
    更有可能的是鳥類運輸：或者是通過外部途徑，即由于種籽偶然粘附在羽毛上;或者是通過內部方式，即由于鳥類吞食果子并隨后將種籽排泄出來。
    難句類型 ：復雜修飾、插入語、倒裝
    解釋：句首有一個倒裝，正常語序是bird transport is more probable.后面的句子中由于插入部分的頻繁出現(xiàn)使句子顯得十分凌亂。
    意群訓練：More probable is bird transport,either externally,by accidental attachment of the seeds to feathers,or internally,by the swallowing of fruit and subsequent　excretion of the seeds.