为什么it is belived that是错的!而要改成it is believed that

为什么it is belived that是错的!而要改成it is believed that it is believed that it is generally believed that It is believed that society would... it is general belived that health is vital important.这句话哪里错了 It is advised that,It is believed that,It can be argued that 'it is believed that +从句' 中that可以省略吗? It is generally believed that teaching is____it is a science it is believed that traveling in natural mountains is very__ It is generally believed that teaching is_____it is a scienc It is generally believed that being hard-working is just____ it is generally believed that true friendship is like health