不一定要加过去分词:
should be用，这里的be是系动词 ，should be后⾯加形容词，副词或者⽅位名词。
如:
Everyone should be here on time.大家都应该按时到
It should be a nice day tomorrow.明天应该是个好天⽓。
He should be home by now.他现在应该在家。
含情态动词的被动语态: can/may/must/should…+be +过去分词
如:
A new puter center (should be built) in our school.
过去将来时的被动语态:
(1).would / should + be + 动词的过去分词 (2).was / were +going to be + 动词的过去分词.
如:
She said that some new factories would be built soon in our city.
He thought that your watch was going to be mended after an hour.
