The PAST PROGRESSIVE TENSE indicates continuing action, something that was happening, going on, at some point in the past. This tense is formed with the helping "to be" verb, in the past tense, plus the present participle of the verb (with an -ing ending): I was riding my bike all day yesterday.
Reptiles. "They are such reptiles
What do you mean by this question?
Answer:
Another word might be explained.
Explanation:
Explained isn’t a informal word, but can be used for both, but it isn’t formal.