Tense represent the time and duration in which the work has happened. Past, present and future are the three types of tenses used with the verbs.
In question 20, the correct tense from the given two options was to be picked. Tense is used according to the subject and the time in which the action took place. All the actions in the given sentences had occurred in the past tense.
In question 21, the correct word or phrase that would help the sentence to become a complete sentence was to be added.
The opposite of suffering is pleasure or happiness. Suffering is often categorized as physical or mental. It may come in all degrees of intensity, from mild to intolerable. Factors of duration and frequency of occurrence usually compound that of intensity.