Bài giảng Chuyên đề ngữ pháp tiếng Anh - Ôn tập: Modals

 Modals
 Chapters 9 & 10
Your Trip to the Southwest: 
 Native American Rock Art 1 Use must or have to to express necessity.
In other areas, you have to hike up to caves or 
into canyons to see the rock art.
 Can you see the rock art from your car?
 NO
 What is necessary to see the rock art?
 You have to leave the car and hike up to 
 caves or into canyons.
 3 Should and ought to are used to express 
advisability.
 You should see the rock art in New Mexico.
 SameYES meaning?
 You ought to see the rock art in New Mexico.
 5 Practice 1
Write a sentence for each of the modals.
 must have to don’t have to ought to should
 1. ______________________________________.
 2. ______________________________________.
 3. ______________________________________.
 4. ______________________________________.
 5. ______________________________________.
 7 The rock art spans thousands of years and an area 
that includes almost all of the United States and 
Mexico. However, the southwestern states contain an 
unusually high number of images, often clustered 
around old settlements. As you walk through these 
areas, you may find figures of people, animals, or 
plants carved into the rock. You can also see unique 
geometric patterns. What were these patterns 
supposed to represent? We may never know. The 
artists could have been illustrating rain or lightning. 
Or they may have been trying to depict emotions 
such as joy or sadness. Whatever the meaning, the 
beauty they had intended to convey is plain to see.
 9 Progressive form of modals express a possibility 
about something in progress, either now or in the 
past.
 The artist could have been illustrating rain. 
 modal + have been + -ing
 When did the artist live? in the past
 What were they doing? illustrating rain
 Are we certain? No. 
 Perhaps they were.
 11 13 Degrees of Certainty: present tense
 The rock art must tell a story.
 The rock art could depict visits from aliens.
 Which one is more certain?
 must 95% sure
 may
 might 50% sure or less
 could
 15 Negative: In both present and past, the degrees of 
certainty for modals change (except for must).
 PRESENT
 The rock art may not tell a story.
 The rock art couldn’t depict visits from aliens.
 Which one is more certain?
 couldn’t 99% sure
 can’t
 must not 95% sure
 may not 50% sure
 might not or less
 17 Practice 3
Use Degrees of Certainty modals to answer the 
questions in your own words. Many answers are 
possible.
 1.Why were the petroglyphs made?
 2.What did the geometric patterns mean?
 3.What is the most frequently seen image in 
 the rock art?
 4.What image probably is not seen in the rock 
 art?
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