6. Fill the spaces in the following sentences by using one

6. Fill the spaces in the following sentences by using one of these forms + the perfect infinitive of the verbs in brackets.
must + perfect infinitive is used for affirmative deductions can't/couldn't + infinitive is used for negative deductions. needn't + perfect infinitive is used for a past action which Was unnecessary but was performed.
11. I phoned you at nine this morning but got no answer. I'm sorry. I .. (be) in the garden. 12. I left my bicycle here and now it's gone. Someone ... (borrow) it. * 13. When she woke up her watch had vanished. Someone ... (steal) it while she slept. 14. I've opened another bottle.
You ... (do) that. We've only just started this one. 15. The machine said, "You weigh 65 kilos," and I said, "Thank you." You ... (say) anything. 16. I told him to turn left and he immediately turned right! He ... (understand) you. 17. Perhaps he swam across. No, he ... (do) that; he can't swim. 18. Do you remember reading about it in newspapers? No, I ... (be) abroad at the time. 19. He ... (walk) from here to London in two hours. It isn't possible. 20. He was very sick last night. The meat we had for supper ... (be) good.