1 Dinosarus ( not live) now 2 What we ( know)

1 Dinosaurs are not living now.

 2 What do we know about them?

 3 They lived 150 million years ago.

The first sentence is in Present Continuous. Present Continuous is used for an action that takes place at the moment of speech. Present Continuous is formed with the help of the auxiliary to be and the suffix ing.

The second sentence is in Present Indefinite. Present Indefinite is formed with the help of the suffix s or es in the third person singular. The auxiliary verb of this tense is to do. We use this auxiliary in negative and interrogative.

The third sentence is in Past Indefinite. We form this tense with the help of the suffix ed for regular verbs.  For Irregular we use the second form of verbs.