Tense:
If you refer to fictional action, you have to use the present. “When Nick enters, Gatsby is walking restlessly up and down.”
(The progressive form is used to show “duration”. On the other hand, “duration” must be limited. If there is no limited duration or the action is repeated regularly, you use the simple form: I go to school at 7.30 every day.
So if you say you are living in Heidelberg, you also say that this is only for a limited time. If you say I live in HD there is no indication that you are planning to move away.
The progressive can also be used with always especially if you want to show that the frequency (repeated action) annoys the speaker:
He is always losing his keys. Or: Tom always goes away at weekends.
(Also mind the position of the adverb) What can you say about the position of adverbs?
Which is the difference between the following sentences? (They are not quite realistic)
Little Mary is behaving badly.
Little Mary behaves badly.
The use of the definite article
1. The definite article is used when the object of group of objects is unique or considered to be unique: the earth, the sea, the sky, the equator, the stars.
2. Before a noun which has become definite as a result of being mentioned a second time:
His car struck a tree; you can still see the mark on the tree.
3. Before a noun made definite by the addition of a phrase or clause:
the girl in blue, the man with the banner, the boy that I met, the place where I met him.
4. Before a noun which by reason of locality can represent only one thing:
Ann is in the garden. Please pass the wine.
5. Before superlatives and first, second, etc. used as adjectives or pronouns and only
the first (week), the best day, the only way
6. The+singular noun represents a class of animals or things: The whale is in danger.
exception: man: If oil supplies run out, man may have to fall back on the horse.
7. The+adjective represents a class of people: the old, the poor etc.
8. The is used before certain proper names: the Atlantic, the Netherlands, the Alps, the Mall, the Gulf of Mexico (of-construction)
9. The is used with names of people: the Smiths etc.
