He's a worm, so that would be a physical impossibility.

他是一只蠕虫， 所以这在物理上是不可能的。

There must sometimes be a physical impossibility in the male element reaching the ovule, as would be the case with a plant having a pistil too long for the pollen-tubes to reach the ovarium.

有时雄性成分到达胚珠在物理上是不可能的， 例如雌蕊太长以至于花粉管无法到达子房的植物就是这种情况。