I'm making a deduction about a present situation. (a. Ben might not come today. I don't know. / b Helen must be at home. Her lights are on. / c They must have been late yesterday.)
B (A: future; C: past)
25
I'm making a deduction about a past situation. (a She didn't answer her phone. She might have left on her vacation this morning. / b He can't be on vacation. I saw him at school. / c They must be really happy.)
A (might have left)
10
I'm sure something is true about the present. (a She couldn't have forgotten her own name! / b When she answered the phone, it must have been her mother calling. / c Joe has been running for hours. He must be tired!)
C (must be)
20
I'm sure something ISN'T true about the present. (a They can't be from France. They don't speak French. / b He must be really good at German. с I think he may be from Sweden.)
A (can't be)
10
I think something is possibly true about the present, but I'm not sure. (a It can't be Gerald's car, because he doesn't have a car. / b Liz might be in her room. Go and see. / c That must be lan's bag. It has his name on it.)
B (might)
20
I'm sure something is true about the past. (a You must be Tom. Is that right? / b Those might be Michelle's keys. /c He isn't here. He must have gone home.)
C(must have gone)
15
I'm sure something ISN'T true about the past. (a They must be in the teachers' room because they aren't in the office. / b She couldn't have forgotten the meeting. I reminded her this morning. / c I think they may have left at about 10.)
B (couldn't have forgotten)
20
I think something is possibly true about the past, but I'm not sure. (a I think Lee might have won the lottery. / b They must have gone out, because they aren't here. / c Kate might be late to the meeting.)
