Andy: Why won’t Stephen answer his mobile phone? Nigel: He (1) must have switched (must / switch) it off while he was playing football and forgotten to turn it back on again.
Andy: He (2) can’t have turned (can’t / turn) it off for that reason because he didn’t have football training today--it was cancelled.
Nigel: Well, he (3) may not have heard (may not / hear) it, or he (4) could have left (could / leave) it at home. Try ringing again. He (5) might answer (might / answer) this time. Anyway, why do you want to call him?
Andy: I want to remind him that he’s coming round to my house today after school. He (6) might have forgotten (might / forget)--you know what he’s like.
Nigel: He (7) can’t have forgotten (can’t / forget)--he was talking about it yesterday and he was looking forward to it.
