The past perfect is a tense in English that you use to talk about events in the past that happened before another action in the past.
The going to-future is a tense in English to talk about the future. You use it to express your opinion or to talk about your intentions.
The past continuous is used to talk about long actions in the past or when the focus is on the duration of the action. This is an exercise about forming it.
The past simple is an important tense in English to talk about actions, habits or events in the past. This is an exercise on how to form negative sentences.