情态动词用法
情态动词用法和练习
* 情态动词也可称为"情态助动词 (Modal Auxiliaries)"，因为它和基本助动词(be, do, have)都属于助动词类。
* 情态动词和其他动词连用，可表示说话人的语气。
* 情态动词可表达建议、要求、可能和意愿等。
* 情态动词没有人称和数的变化。
* 常用的情态动词有：can, could, may, might, must, shall, should, will, would
这九大情态动词；其他的还有ought to, need, dare 等。
一、情态动词的变化：
1.1 简单型(Simple)：表示现在或将来的状态
I could work (动词不可加 to ，如：to work。下同)
you could work
he could work
she could work
it could work
we could work
they could work
1.2 完成式型 (Perfect)：表示过去的状态
I could have worked (动词是 have + v-ed 过去分词。下同) you could have worked
he could have worked