Modals

情态动词

A modal is a helping verb. It is always followed by a base verb no matter the subject is singular or plural.

情态动词是助动词，无论主语是单数或复数，情态动词后的动词必须保留原行。

       e.g.

       I must complete all my homework before bedtime.

The negative form of a modal is formed 

by adding ‘not’ after it.

我们在情态动词后加“not”，以构成它的否定式。

       e.g.

       He could not finish the soup.

       We must not play on the road.

Must, could, can, should and may are examples of modals:

情态动词的例子包括 must、could、can、should 和 may；

**   must is used to show necessity;

       must 用于显示必要性；

       e.g.

       We must clean the house before 

       Mum comes home.

**   could is used to show abilities in the past

       or to ask for a favour in a polite way;

       could 用于显示过去所拥有的能力或

      有礼貌的请求；

       e.g.

       My grandfather could swim very well 

       when he was young.

       Could you help me carry those bags?

**  can is used to show abilities or something 

      that someone is able to do;

      can 用于显示能力或可以做的事；

      e.g.

      Most birds can fly.

      I can lend you that book if you want.

**   should is used to give advice, opinions 

       or to express obligations;

       should 用于表达劝告、意见或义务；

       e.g.

       You should do as your mother told you.

**   may is used to show uncertainly or 

       to ask for permission.

       May 用于显示不确定性或征求同意。

       e.g.

       I may visit her today or tomorrow.

       May I go home now?