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12.7 past obligation should have + past participle, had to, was supposed to 1.
Must has no past form. When you refer to a past obligation that was fulfilled (i.e. you did what
you were obliged to douse had to, didn’t have to. 2.
Was / were supposed to is used to refer to something that you were obliged to do in order to comply with some authority, but in reality did not do.
3.
Should have + past participle is used to refer to something that you did not do, but it would have been better if you had done it.
4.
Was going to is used to refer to what you were planning
to do but did not dob YES NO 1 Web had to perform six experiments to ensure repeatability. Web mustedb perform six experiments to ensure repeatability.
2 The manuscript
was supposed to have been completed last week, but unfortunately they are still working on it. The manuscript
had to be completed last week, but unfortunately they are still working on it.
3
Web should have sent the Abstract to the conference, then we could have presented our research. Now we can only go and watch. Web had to send the Abstract to the conference, then we could have presented our research. Now we can only go and watch.
4 I
was going to send my Abstract to the conference organizers, but I forgot. I
had to send my Abstract to the conference organizers, but I forgot.
