例句：
When should you prune apple trees?
蘋(píng)果樹(shù)應(yīng)該什么時(shí)候剪枝？
Should police officers carry guns ?
警察應(yīng)該佩槍嗎？
No income should remain undeclared.
一切收入均應(yīng)申報(bào)。
The selectors should resign en bloc.
這些選擇者應(yīng)該集體辭職。
You should have seen it!
你應(yīng)該看見(jiàn)的！