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« Last post by hide on May 16, 2022, 11:48:25 am »
Help me, please.
The original sentences are:
Australia's plants and animals are just about the closest things to alien life you are likely to encounter on Earth. That's because Australia has been isolated from the other continents for a very long time - at least 45 million years. #1 The other habitable continents have been able to exchange various species at different times because they've been linked by land bridges. Just 15,000 years ago it was possible to walk from the southern tip of Africa right through Asia and the Americas to Tierra del Fuego. Not Australia, however. Its birds, mammals, reptiles and plants have taken their own separate and very different evolutionary journey, and the result today is the world?s most distinct - and one of its most diverse - natural realms.
Can I change #1 into #2?
#1:The other habitable continents have been able to exchange various species at different times
because they've been linked by land bridges.
#2 The other habitable continents have been able to exchange various species at different times
because they were linked by land bridges.
I don't think it's OK, because I think that the other habitable continents have been able to exchange various species at different times because they have been linked by land bridges, not because they were ( linked ) in the past. In this sense, they are still linked, so they are now able to and will be able to exchange species as long as they are linked by land bridges from now on. But as for Australia, it has not been able to exchange species with the other continents because it was separated from the other continents at least 45 million years ago and it has been isolated from the other continents since then.
So, it should be #1:
The other habitable continents have been able to exchange various species at different times
because they have been linked by land bridges.
What do you say about this?