it_(difficulty) for human beings to predict weather in the past
问题描述：
it_(difficulty) for human beings to predict weather in the past
答
It ( was difficult ) for human beings to predict weather in the past .
be diffcult for somebody to do sth 意思是“对某人来说,做某事很.”
翻译：在过去对于人类来说预测天气是很困难的.