1. EfS Grammar I: Two Present Tenses – Simple and Continuous
Explaining how things work and describing what is happening.

2. Simple - Affirmative
I you he/she/it we they
to be am
are is
to have got
have got
has got
to work
work
works
"One s" rule: The third person is either plural (a noun would end in "-s") or the verb ends with "-s".

3. Simple - Negative
I you he/she/it we they
to be
am not
are not
is not
to have got
have not got
has not got
to work
do not work
does not work
"One s" rule: Where an "s" is added, it is added to the auxiliary verb (be, have, do).

4. Simple - Interrogative
to be
am I?
are you?
is he?
are we?
are they?
to have got
have I got?
have you got?
has she got?
have we got?
have they got?
to work
do I work?
do you work?
does he work?
do we work?
do they work?
"One s" rule: "s" is added to the auxiliary verb. Subject and first verb are inverted.

5. Spelling rules
When adding an "s" to the verb:
Normally just add -s
-s, -z, -sh, -ch, -o word endings add -es
-y word ending consonant –y changes to –ies vowel –y goes to -ys

6. Continuous – All Forms
Affirmative (Negative)
I am (not) doing
you are (not) doing
he/she/it is (not) doing
we are (not) doing
they are (not) doing
Interrogative
am I doing?
are you doing?
is he/she/it doing?
are we doing?
are they doing?
Form: to be + present participle (-ing form)

7. Present Participle - Spelling
Present participles are formed by adding -ing
The final consonant may be doubled: Mainly in one-syllable verbs ending with consonant-vowel-consonant, e.g. stop – stopping
Words ending in –ie: -ie changes to –y, e.g. lie – lying
Words ending in –e: final –e is dropped, e.g. make - making

8. Simple and Continuous - Use
Simple is used:
to explain something in an expository text;
to express repeatedness of an action;
to express completedness of an action;
with verbs of state.
Continuous is used:
to express incompleteness of an action;
and therefore sometimes temporariness.

9. States and Actions
Some verbs may be either verbs of state or verbs of action and their meaning changes accordingly:
to see (a state): is an involuntary action.
to see someone (an action): is to meet that person and talk to him/her.
to feel (a state) is an emotion.
to feel something (an action) is to move your fingers over an object.

10. Examples in Technical Texts
In describing the characteristics of something (typifying) we use the present simple e.g.:
"Organisms play an important role in the water cycle."
"These nitrogen-fixing bacteria come in three forms."
Dave McShaffrey: Ecosystems
The present continuous is used only rarely, e.g.:
"The main concepts we are trying to get across in this section [...]"
McShaffrey (2006)

11. What is wrong with …?
Graham is speaking 5 languages.
What??? All at the same time?
The River Thames is flowing into the North Sea.
And tomorrow into the Irish Sea...
I take tennis lessons this summer.
"This summer" suggests that the action is incomplete or temporary.

12. Reference
McShaffrey, Dave (2006): Environmental Biology – Ecosystems. ~biol/102/ecosystem.html, accessed April 5, 2009.
Alternative citation style: marietta.edu