Q

Why does a cat look first to one side and then to the other side when it enters a room?
为什么猫进入房间的时候先看房间的一边，再看另一边？

A

Because it can't see both sides at once.
因为它不能一次看两边。

点睛一笔

one side指“一边”，the other side指“另一边”，两边在相反的方向上，所以不能同时被看到。