例句：
When should you prune apple trees?
蘋果樹應(yīng)該什么時候剪枝？
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。
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)該看見的！