Question

Modal verbs of speculation and deduction - past 4 Look at these sentences and complete the rules below with the verbs in blue. a He must have made a lot of money from Bitcoins. b It can't have been him because he didn't know what Bitcoins were! c He may/might/could have used a Japanese pseudonym. d He mightn't/may not have been the inventor. 1 We use and when there is a 50% possibility that something was true, but we cannot use in the negative form with this meaning. 2 We use when we are 90% certain that something was true. 3 We use when we are 90% certain that something wasn't true. GRAMMAR REFERENCE PAGE 68 centences.​

Answer 1

Certainly! It seems like you have sentences using modal verbs of speculation and deduction in the past. Let's go through each sentence and complete the rules:

a) "He must have made a lot of money from Bitcoins." Rule: We use "must have" when there is a 95-100% certainty that something was true in the past.

b) "It can't have been him because he didn't know what Bitcoins were!" Rule: We use "can't have" when we are 95-100% certain that something wasn't true in the past.

c) "He may/might/could have used a Japanese pseudonym." Rule: We use "may have," "might have," or "could have" when there is a 50-50 possibility or less, indicating uncertainty about something in the past.

d) "He mightn't/may not have been the inventor." Rule: We use "mightn't have" or "may not have" when there is a possibility (less than 50%) that something was not true in the past.

Now, let's complete the rules:

1) We use "and" when there is a 50% possibility that something was true, but we cannot use it in the negative form with this meaning.

2) We use "must have" when we are 90% certain that something was true.

3) We use "can't have" when we are 90% certain that something wasn't true.

GRAMMAR REFERENCE PAGE 68: Sentences using modal verbs of speculation and deduction in the past.