Possessive Pronoun and The Simple Present Tense

1.1. Possesive Pronoun
Possesive pronoun is a pronoun that can take the place of noun phrase to show ownership (like “ That car is mine”.)
 The weak possesives (also called possessive determines) function as determines infront of  nouns (as in “ My mom is eating French Fries”. The weak possesives are my, your, his, her, its, our and their.
In contrast, the strong (or absolute) possessive pronouns stand on their own : mine, his, yours,hers, its, ours, and theirs. The strong possessive is a type of independent genitive.

• Examples and Observations
1. “ Go on and get inside the TARDIS. Oh, never given you a key? Keep that. Go on, that’s yours.  Quite a big moment really!”
(The Doctor to Donna in the “The Poison Sky”. Doctor Who, 2005)

2. “ Those who restrain desire, do so because theirs  is weak enough to be restrained.”
(William Blake, The Marriage of Heaven and Hell, 1790 – 1993)

3. “ It’s really hard to be roommates with people if your suitcases are much better than theirs.”
(J.D. Slinger, The Catcher in The Rye, 1951)

• Possessive Pronouns vs Possessive Determines
The possessive pronouns (mine, yours, his etc.) are like possessive determiners, except that they constitute a whole noun phrase.
o The house will be hers you see when they are properly divorced.
o Writers have produced extraordinary work in conditions more opressive than mine.

Posessive Pronouns are typically used when the head noun can be found in preceeding context, thus in 1, hers means ‘her house’, and in 2,  mine means ‘my conditions.’ Here the posessive pronoun is parallel to the elliptic use of the genitive.
(D. Biber, S. Conrad, and G. Leech, Longman Student Grammar of Student and Written English. Pearson, 2002)

- "[The] construction with the possessive pronoun [e.g. a friend of mine] differs from the alternative of possessive determiner + noun (e.g. my friend) mainly in that it is more indefinite. The sentences in (30) below illustrates this point.
(30) a. You know John? A friend of his told me that the food served at that restaurant is awful.

(30) b. You know John? His friend told me that the food served at that restaurant is awful.
The construction with the possessive pronoun, in (30a), can be used if the speaker hasn't specified and doesn't need to specify the identity of the friend. In contrast, the construction with the possessive determiner, in (30b), implies that the speaker and listener both know what friend is intended."
(Ron Cowan, The Teacher's Grammar of English: A Course Book and Reference Guide. Cambridge University Press, 2008)

1.2. Simple Present Tense
1. To express habits, general truths, repeated actions or unchanging situations, emotions and wishes:
I smoke (habit); I work in London (unchanging situation); London is a large city (general truth).

2. To give instructions or directions:
You walk for two hundred meters, then you turn left.


3. To express fixed arrangements, present or future:
Your exam starts at 09.00

4. To express future time, after some conjunctions: after, when, before, as soon as, until:
He'll give it to you when you come next Saturday.

Be careful! The simple present tense is not used to express actions happening now.

1.2.1. EXAMPLES
- For habits
He drinks tea at breakfast.
She only eats fish.
They watch television regularly.

- For repeated actions or events
We catch the bus every morning.
It rains every afternoon in the hot season.
They drive to Monaco every summer.

- For general truths
Water freezes at zero degrees.
The Earth revolves around the Sun.
Her mother is Peruvian.

- For instructions or directions
Open the packet and pour the contents into hot water.
You take the No.6 bus to Watney and then the No.10 to Bedford.

- For fixed arrangements
His mother arrives tomorrow.
Our holiday starts on the 26th March

- With future constructions
She'll see you before she leaves.
We'll give it to her when she arrives

1.2.2. Forming The Simple Present Tense : TO THINK

1.2.3. The Simple Present Tense for Third Person Singular
- In the third person singular the verb always ends in -s:
he wants, she needs, he gives, she thinks.

- Negative and question forms use DOES (= the third person of the auxiliary 'DO') + the infinitive of the verb.

He wants ice cream. Does he want strawberry? He does not want vanilla.

- Verbs ending in -y : the third person changes the -y to -ies:
fly : flies, cry : cries
Exception: if there is a vowel before the -y:
play : plays, pray : prays

- Add -es to verbs ending in:-ss, -x, -sh, -ch:
he passes, she catches, he fixes, it pushes

1.2.3.1. EXAMPLE
• He goes to school every morning.
• She understands English.
• It mixes the sand and the water.
• He tries very hard.
• She enjoys playing the piano.

Source :
http://grammar.about.com/od/pq/g/posspronterm.htm
http://www.ef.com/english-resources/english-grammar/simple-present-tense/