湖南省株洲市第四中学高中英语必修4：Unit 2《Section Four Grammar and usage》（译林版必修4）同课异构课件 1.ppt

Unit 2 Sports events Can 和 be able to Ought to / should Have to / must Have to / must might / may/ could / should / ought to / will / must can / could / may / might will / can / could / would shall make offers make offers/ give advice 和其他时态的连用 must have done 的反意疑问句 * * Grammar and usage 情态动词没有人称和数的变化，有词义，但是不完整，不能单独做谓语，必须和不带to的动词不定式连用。 ability certainty permission obligation make requests make suggestions make offers give advice 能力 义务, 责任 确定 允许 提出请求 提出建议 提供帮忙 提出忠告 Modal verbs: general introduction (1)He can run the 100m sprint in 11 seconds. (2)Can this little girl read before she goes to the primary school? ability can表示可能性时，指的是理论上的可能，它通常不用来表示某事实际发生的可能性或真实性。如： Accidents can happen．Anybody can make mistakes． can / be able to can/be able to ability 在过去时态的肯定句中需要某种条件或努力做成某事，我们要用was／were able to而不能用could。如： It was a holiday and the children were able to go to the seaside． The girl worked hard so she was able to pass the final test． I’m sorry I haven’t been able to play tennis with you recently. obligation ought to/should ought to与should意思接近，大多数情况下二者可以互换，但是should谈的是自己的主观看法, 用于各种人称。 ought to则更多反映客观情况，在谈到法律、义务和规定时使用。如： We should／ought to help each other and learn from each other in our work． You shouldn’t spend so much time playing. She is your mother, so you ought to support her． Ought he to go? Yes, I think he ought (to) . have to/must obligation must与have to都可以表示“必须”的意思，但要注意以下两点区别。 1) must只有现在时，而have to有现在时、过去时和将来时。如： We must work hard, or we’ll fail in the examination． Two years ago, the poor girl had to leave school for lack of money． 2) must表示主观看法，have to则侧重于客观需要。如： We must be strict with ourselves in everything． In cities with many cars, some people have to wear masks． obligation have to/must She might win a medal at the Olympics. She may be at home now. She could read and write at the age of 4. She should come to join us. She ought to/will/must help me whenever I am in trouble. certainty might/may/c