to demand that troops be / should be withdrawn - требовать вывода войск
one should do the best he can - нужно делать всё возможное
one should not tamper with a jury - на суд не следует оказывать давление
children should be seen, and not heard - в обществе взрослых дети должны молчать
to command that work should cease - отдать команду о прекращении работы
this should liven up the debate no end - это должно чрезвычайно оживить дебаты
it should seem - казалось бы
you should consult a doctor - вам следует обратиться к врачу
we should go now - нам пора /надо/ уходить
which is as it should be - как и следовало ожидать
shall: You use shall with 'I' and 'we' in questions in order to make offers or suggestions, or to ask for advice .
should've: Should've is the usual spoken form of 'should have', especially when 'have' is an auxiliary verb .
as who should say: as if one should say
would/should be obliged: If you tell someone that you would be obliged or should be obliged if they would do something, you are telling them in a polite but firm way that you want them to do it.
I would be obliged: expressions used to tell someone in a polite but firm way that one wants them to do something