苏州云盾消防:what has happened是什么意思 请明确解释一下

what has happened?是什么意思 为什么用HAS what has happened是什么意思 请明确解释一下 Neither he nor his parents___(vare) what has happened. Neither he nor his parents___(care) what has happened. It shows what has happened to the forests of the USA in the last 350years. WHAT HAD HAPPENED这是什么形式 求讲一下 what it has happened to to the forest for the USA in the last 350 years ?这样对吗？为什么？ What happened in this code? 1066what happened in england? what happened to the titanic?(in English)