Unit 2.Honesty Is the Best Policy

In unit 2,we disuss the use of modals to talk about how sure or not we are of something. The modals are used with the tenses present , past and future.
For the past  of modals we add  the auxiliary verb have and past participle.
Examples: 
Almost Certain:You must be joking.
Almost Certain(Imposible):He couldn’t have been in the office. 
Quite sure:She should be here soon.
Less certain:You could be a millionaire soon.