he suggested that the trip to park be more interesting为什么是要用Be呢,而不用is,was,would be?

he suggested that the trip to park be more interesting
为什么是要用Be呢,而不用is,was,would be?

当 suggest 作“建议”讲时,应该用虚拟语气.
可接that宾语从句,that从句用should+动词原形,should可以省略.
例如：
She suggested/advised/proposed that the class meeting (should) not be held on Saturday.她建议班会不要在星期六举行.
We suggested/advised/proposed that he (should) go and make an apology to his teacher.我们建议他去向老师道歉.

他建意这次旅行去公园会更有意思

他的建议是：去公园会更加有趣。 哦，sugget是建议的意思，后面的从句要用虚拟语气，即：should do的形式，should可以省略。