should 后面是不是原型

should属于情态动词，情态动词后面都加动词原型

should
should
v.aux.（助动词）
shall的过去式
Used to express obligation or duty:
应该：用来表示义务或职责：
You should send her a note.
你应该给她留一个条
Used to express probability or expectation:
用于表示可能性或期望：
They should arrive at noon.
她应该在中午到达
Used to express conditionality or contingency:
用于表示可能性或可能发生的事件：
If she should fall, then so would I.
如果她失败了，那我也会失败
Used to moderate the directness or bluntness of a statement:
用于使一个直接或直率的陈述变得婉转：
I should think he would like to go.
我倒是认为他愿意去

Like the rules governing the use ofshall and will on which they are based, the traditional rules governing the use ofshould and would are largely ignored in modern American practice. Eithershould or would can now be used in the first person to express conditional futurity:
就象作为shall 和 will 词的基础的限用的用法规则一样， 适用于should 和 would 这个词的传统使用规则在现代美国英语中也已被忽略了。 现在should 或 would 这两个词中的任何一个都可以用于第一人