前文是 The simplest wayto explain what I‘ve learned frommy life in Africa is through a parable about why human beings have two ears butonly one tongue.
Why is this？Probably so that we have to listen twice as much as we speak.
意译为“为何如此？可能是为了让大家少说多听。”
Probably so that we have to listen twice as much as we speak.补充完整就是This is probably so that we have to listen twice as much as we speak.
主干为This is so that从句（类比It is because从句），假如把be看作是系动词，那so that引导表语从句；假如把be看作不及物动词，so that则引导状语从句。
we have to listen twice as much as we speak.则是一个as ... as比较结构，听是说的两倍——听的要比说的多一倍。
