Common Grammar Mistake: the use of Simple Past Tense and Present Perfect Tense

When it comes to writing, I have always been having problems to deal with the use of tenses, specifically simple past tense and present perfect tense. Frankly speaking, I did not know the actual difference between the two until I am assigned to do this portfolio. All I knew was that the two tenses are referring to past events, but when to use which, I was confused. Therefore, I always write according to my intuition whenever I come across this.

After reading from a few sources, I have learnt a lesson. The difference between simple past and present perfect tense is quite distinguishable. All we have to do is simple: keep our mind clear. If there is a clear indication that the event is happened in the past, use simple past tense. Otherwise, we must consider whether the action in the past affects the present in anyway. Table 1 compares the use of simple perfect tense and present perfect tense:

Simple Past Tense	Present Perfect Tense
The past simple tense may describe completed activities and past situations.	The present perfect tense may describe activities or situations which began in the past and are still continuing
In 1976, 60% of families were couples with children. In 1981, 34% of children aged 20-24 lived with their parents.	The number of one person households has grown. Over the past twenty years, the average size of households has fallen.
The past simple may describe activities without linking them to the present.	The present perfect may describe completed activities whose impact is felt in the present
They completed the research in 1972. They arrived yesterday.	They have completed the research. (Meaning: a short time ago; here it is). They have arrived. (Meaning: a short time ago; here they are).
With past simple verbs, the time may be specified.	With present perfect verbs, indefinite time expressions may be used
They completed the research in 1972. They arrived yesterday. The number of one person households grew last year.	They have just completed the research. They have already arrived. The number of one person households has grown recently.

Table 1: Present perfect and simple past compared (Monash University, 2007)

Simple Past Tense	Present Perfect Tense
yesterday 10 minutes ago last week in 1993 this morning/ this afternoon (when the period is finished)	just lately recently this morning/afternoon/evening (when the period is not finished) since

Table 2: Time markers for simple past tense and present perfect tense (Singh & Holden, 2006)

Table 2 gives some examples of time markers or signals that we should look out for when we are deliberating to write in simple past tense or present perfect tense. These markers serve as clues which guide us to write the right tenses.

Doing exercises is essential to master grammar. Feel free to try the exercise below to test your understanding. After all, practice makes perfect.

Simple Past Tense and Present Perfect Tense Exercise

Since computers were first introduced to the public in the early 1980's, technology 1._____ (change) a great deal. The first computers 2._____(be) simple machines designed for basic tasks. They 3._____(have, not) much memory and they 4._____(be, not) very powerful. Early computers were often quite expensive and customers often 5._____ (pay) thousands of dollars for machines which actually 6._____(do) very little. Most computers 7._____ (be) separate, individual machines used mostly as expensive typewriters or for playing games.

Times 8._____ (change). Computers 9._____(become) powerful machines with very practical applications. Programmers 10._____(create) a large selection of useful programs which do everything from teaching foreign languages to bookkeeping. We are still playing video games, but today's games (become) faster, more exciting interactive adventures. Many computer users 11._____(get, also) on the Internet and (begin) communicating with other computer users around the world. We 12._____(start) to create international communities online. In short, the simple, individual machines of the past 13._____ (evolve) into an international World Wide Web of knowledge.

Answers:

1. has changed
2. were
3. did not have
4. were not
5. paid
6. did
7. were
8. have changed
9. have become
10. have created
11. have become
12. have also got
13. have begun
14. have started
15. have evolved

(Englishpage.com, n.d.)

References

Englishpage.com. (n.d.). Verb Tense Exercise 6: Simple Past/ Present Perfect. Retrieved 10 September, 2008, from http://www.englishpage.com/verbpage/verbs6.htm

Holden, A. & Singh, J. (2006). New Remedial English Grammar for KBSM (4^th edition). Selangor: Fajar Bakti Sdn Bhd

Monash University. (2007, February 21). Present perfect and simple past compared. Retrieved 10 September, 2008, from http://www.monash.edu.au/lls/llonline/grammar/tense/2.4.xml