Grammar 51 - Modals - Past

The ‘have’ form is used when modals are used expressing a variety of attitudes or functions, except in the case of expressing ability and obligation. For instance, ‘She could use her father’s computer when she was only 6 years old’ is as acceptable as ‘She could have used her father’s computer when she was only 6 years old’ when expressing ability. ‘You had to halt at the red light’ is as good as ‘you have had to halt at the red light’ when expressing obligation.

In the above sentences modals are not used. Instead we use ‘had to’ and ‘have had to’ as they resemble modals and are often interchanged with them. Other interchangeable phrases are ‘have got to’, ‘have to’ and ‘had better.’

In sentences, where ‘need’ is used to express in the past tense ‘have’ would not be necessary. For instance, in the sentence, ‘You did not need to study lesson number 20’ we have not used ‘have.’

The modals such as ‘must’, ‘should’, ‘could’, ‘might’ and ‘may’ express attitudes and functions in the past tense. It is possible that more than one modal can be used to express certain attitudes while using modals in the past tense. For instance in the sentence ‘That must have been the right store’ it is possible to change ‘must’ to any of the other modals depending upon the context of the sentence.

As is the case in most English sentences, we also use modals in negative sentences by simply adding ‘not’ appropriately. The sentence ‘That must not have been the right store’ is an example of using ‘not.’

Take the quiz that follows and learn the rules of grammar to use when constructing sentences containing modals in the past tense.