It's necessary that you should review your lessons before the examination.
It's a pity that Teresa should have died so young.
I'm surprised that a careful man like him should have made such a mistake.
should用在suggest, ask, order, insist等子句中(这些动词通常指应采取某种行动或应完成某种要求)
I asked that they (should) make a reservation in advance.
The doctor suggested that my father (should) lose some weight.