条件状语从句的问题 it helps us understand the world better if we know
条件状语从句的问题 it helps us understand the world better if we know a little geography. it helps us understand the world better if we know a little geography.这句话属于什么句型?如果是if 引导的条件状语从句为什么不用主将从现,将it helps 改为 it will heip!