Page 17 - Advanced English Grammar in Use

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We use the present perfect when we talk about something that happened in a period of time up to
the present. We use the past simple to talk about something that happened at a particular, finished
time in the past. Compare:
• Science has made many major advances this century, and
• Scientists made some fundamental discoveries in the 18th century.
• He puts to good use things that other people have thrown away, and
• I threw away most of my old books when I moved house.
When we report that someone has recently invented, produced, discovered or written something
we use the present perfect. When we talk about something that was invented, etc. in the more
distant past we use the past simple. Compare:
• Scientist have discovered that, all over the world, millions of frogs and toads are dying.
• It is often said that Hernan Cortes 'discovered' Mexico in 1519.
• Two schoolchildren have invented a device for moving large objects up flights of stairs.
• Chinese craftsmen invented both paper and printing.

Sometimes it makes very little difference to the main sense of the sentence if we think of something
happening in a period of time up to the present or at a particular, finished time in the past:
• The research is now complete and the experiment was {or has been) a success.
• Does it concern you that you failed {or have failed) the test?
• I'm sure I read {or I have read) somewhere that he died in a plane crash.

We can use either the present perfect or the past simple to talk about repeated actions or events. If
we use the present perfect, we often suggest that the action or event might happen again.
Sometimes we emphasise this with phrases such as so far and up to now (see Unit 5). If we use the
past simple, it suggests that it is finished and won't happen again. Compare:
• Timson has made 13 films and I think her latest is the best, and
• Timson made 13 films before she was tragically killed in a car accident.
• Lee has represented his country on many occasions, and hopes to go on to compete in the
next Olympics, and
• Lee represented his country on many occasions, but was forced to retire after an injury.

We can use both the present perfect and the past simple to talk about states. We use the present
perfect to talk about a state that existed in the past and still exists now, and we use the past simple
if the state no longer exists. Compare:
• I have known him most of my working life. (I am still working) and
• I knew him when we were both working in Rome.
• We have belonged to the tennis club since we moved here. (We still belong to it.) and
• We belonged to the tennis club in the village we used to live in.

In news reports, you will often read or hear events introduced with the present perfect, and then
the past simple is used to give the details:
The film star Jim Cooper has died of has N
cancer. He was 68 and lived in Texas...' 'A teacher from Oslo
become the first woman to
'• 'The US space shuttle Atlantis has cross the Antarctic alone. It
took her 42 days to make the
returned safely to earth. It landed crossing with her dog team..."/
in Florida this morning...'
Present perfect and past simple (1) and (3) Past continuous and past simple