martes, 7 de octubre de 2014

PRESENT PERFECT SIMPLE AND CONTINUOUS.







Form
Present Perfect Simple
Present Perfect Progressive
irregular verbs: form of 'have' + 3rd column of irregular verbs
Example:
I / you / we / they have spoken
he / she / it has spoken
regular verbs: form of 'have' + infinitive + ed
Example:
I / you / we / they have worked
he / she / it has worked
form of 'have' + been + verb + ing
 
Example:
I / you / we / they have been speaking
he / she / it has been speaking
Exceptions
Exceptions when adding 'ed' :
  • when the final letter is e, only add d
Example:
love - loved
  • after a short, stressed vowel, the final consonant is doubled
Example:
admit - admitted
  • final l is always doubled in British English (not in American English)
Example:
travel - travelled
  • after a consonant, final y becomes i (but: not after a vowel)
Example:
worry - worried
but: play - played
Exceptions when adding 'ing' :
  • silent e is dropped. (but: does not apply for -ee)
Example: come - coming
aber: agree - agreeing
  • after a short, stressed vowel, the final consonant is doubled
Example: sit - sitting
  • after a vowel, the final consonant l is doubled in British English (but not in American English).
Example: travel - travelling
  • final ie becomes y.
Example: lie - lying
Use
Both tenses are used to express that an action began in the past and is still going on or has just finished. In many cases, both forms are correct, but there is often a difference in meaning: We use the Present Perfect Simple mainly to express that an action is completed or to emphasise the result. We use the Present Perfect Progressive to emphasise the duration or continuous course of an action.
Result or duration?
Do you want to express what has happened so far or how long an action has been going on yet?
Present Perfect SimplE
Present Perfect Progressive
Result (what / how much / how often)
I have written 5 letters. / I have been to London twice.
Duration (how long)
I have been writing for an hour.
Certain verbs
The following verbs are usually only used in Present Perfect Simple (not in the progressive form).
  • state: be, have (for possession only)
Example: We have been on holiday for two weeks.
  • senses: feel, hear, see, smell, taste, touch
Example: He has touched the painting.
  • brain work: believe, know, think, understand
Example: I have known him for 3 years.
Emphasis on completion or duration?
Do you want to emphasise the completion of an action or its continuous course (how has somebody spent his time)?
Present Perfect Simple
Present Perfect Progressive
Emphasis on completion
I have done my homework. (Meaning: My homework is completed now.)
Emphasis on duration
I have been doing my homework. (Meaning: That's how I have spent my time. It does not matter whether the homework is completed now.)
Result or side effect?
Do you want to express that a completed action led to a desired result or that the action had an unwanted side effect?
Present Perfect Simple
Present Perfect Progressive
desired result
I have washed the car. (Result: The car is clean now.)
unwanted side effect
Why are you so wet? - I have been washing the car. (side effect: I became wet when I was washing the car. It does not matter whether the car is clean now.)
Time + negation: last time or beginning of an action?
In negative sentences: Do you want to express how much time has past since the last time the action took place or since the beginning of the action?
Present Perfect Simple
Present Perfect Progressive
since the last time
I haven't played that game for years. (Meaning: It's years ago that I last played that game.)
since the beginning
I haven't been playing that game for an hour, only for 10 minutes. (Meaning: It's not even an hour ago that I started to play that game.)
Permanent or temporary?
If an action is still going on and we want to express that it is a permanent situation, we would usually use the Present Perfect Simple. For temporary situations, we would prefer the Present Perfect Progressive. This is not a rule, however, only a tendency.
Present Perfect Simple
Present Perfect Progressive
permanent
James has lived in this town for 10 years. (Meaning: He is a permanent resident of this town.)
temporary
James has been living here for a year. (Meaning: This situation is only temporary. Maybe he is an exchange student and only here for one or two years.)
Signal words
Present Perfect Simple
Present Perfect Progressive
  • how often
  • ... times
  • how long
  • since
  • for
Exercises on Present Perfect Simple and Present Perfect Progressive