A mystery at sea

What's in the lesson

1. 1Warm-up
2. 2In this lesson
3. 3Guess the words (1)Vocabulary exercise
4. 4Guess the words (2)Vocabulary exercise
5. 5Check the wordsVocabulary
6. 6Check your understandingReading comprehension
7. 7Listen: a cruise through the TriangleListening comprehension
8. 8Use the new wordsVocabulary exercise
9. 9How sure is the guide?Grammar exercise
10. 10Guessing about nowGrammar rule
11. 11Choose the best guessGrammar exercise
12. 12The man in the old houseGrammar exercise
13. 13Say it naturallySpeaking practice
14. 14What is going on?Speaking practice
15. 15Let's discussDiscussion
16. 16Wrap-up

Homework

1. 1Homework: closest meaningVocabulary exercise
2. 2Homework: your sentencesVocabulary exercise
3. 3Homework: make a guessGrammar exercise
4. 4Homework: a mysteryDiscussion

Words

• mysterious/mɪˈstɪriəs/

  strange and hard to explain or understand

• vanish/ˈvænɪʃ/

  to disappear suddenly, often in a way that nobody can explain

• crew/kruː/

  all the people who work on a ship or a plane

• sink/sɪŋk/

  to go down under water (sink, sank, sunk)

• current/ˈkɜːrənt/

  a movement of water in one direction, in the ocean or a river

• theory/ˈθiːəri/

  an idea that tries to explain why something happens

• claim/kleɪm/

  to say that something is true, although it has not been proved

• evidence/ˈevɪdəns/

  facts or things that show that something is true

• investigate/ɪnˈvestɪɡeɪt/

  to try to find out the facts about something, for example a crime or an accident

• wreck/rek/

  what is left of a ship, a plane or a car after a bad accident

Two slides from the lesson

Warm-up

Let's talk about mysteries.

1. Have you ever heard of the Bermuda Triangle? What do you know about it?
2. Do you like mysteries: books, movies, podcasts or true stories?
3. Can you think of something strange that nobody can explain?

Grammar rule

Guessing about now

must, might, could, can't

How sure are you?	Use	Example
Almost sure it's true	must	It must be a reef. (It isn't moving.)
It's possible	might, may, could	It might be a shark. There could be wrecks under us.
Possible it's not true	might not, may not	He might not be home.
Almost sure it's not true	can't (or couldn't)	It can't be a shark. (Sharks move!)

modal + verb, or modal + be + -ing

• It must be a reef. (not It must to be, not It must is)
• He might know the answer.
• For something happening right now: Some of you must be thinking about aliens.
• Not It can be a shark: for a guess, use might, may or could. Can is for things that are sometimes true: Storms can be dangerous.

must not

In American English, must not is also common for a negative guess: He must not be home. The lights are off. Use can't when something seems impossible: That can't be true!

These are guesses, not rules. "You must wear a seat belt" is a rule, but "You must be tired" is a guess.