Cover of the textbook Outcomes Upper-Intermediate - Student's Book

The key answer of exercise 7

The key to exercise solutions in chapter 16 - The mother of invention for the textbook Outcomes Upper-Intermediate - Student's Book with authors Hugh Dellar and Andrew Walkley from National Geographic Learning

Question

Read the Grammar box. Then look at the mistakes crossed out in the sentences below. Work in pairs. Discuss how you think each sentence should be corrected and why.

Answer

  1. having to (need -ing form after a preposition)
  2. let (let is the only possibility as it is not followed by to)
  3. forced (because made is followed by infinitive without to)
  4. be able to (can can’t be used after will)
  5. have been able to (can doesn’t have a past form – present perfect needed with over the last few years)
  6. to allow us to / to enable us to compete
  7. were able to (to express ‘can’ in the past)
  8. had to; made (had to to express ‘must’ in the past; made is followed by the infinitive without to)
  9. have to (infinitive form to express ‘must’)
  10. be able to; let (let is the only possibility as it is not followed by to)