chance vs. opportunity

[Englishlanguage]

Hello,
Which word would you use in the following sentences?

1) When I was offered a place on a cycling tour of Cuba in aid of a national charity, I decided it was a chance/opportunity that I wasn't prepared to turn down

2) He found his new job incredibly boring, so made the decision to get out of it at the earliest chance/opportunity and look for something more exciting and challenging

[Clare James]

Although the two words have very similar meanings, these are problems with collocations. (Common patterns of native speaker usage.)

For the first sentence 'to turn down an opportunity' is the stronger collocation here. (Usually you say 'to miss a chance'.)

For the second sentence 'at the earliest opportunity' is the collocation.

For a good self-study book to improve your awareness and use of collocations, try 'Check Your Vocabulary for Natural English Collocations' by Alison Wooder and Jon Marks.
Amazon.co.uk: Check Your Vocabulary for Natural English Collocations: All You Need to Improve Your Vocabulary (Check Your Vocabulary): Books: Jon Marks,Alison Wooder

[Englishlanguage]

Originally Posted by Clare James

Although the two words have very similar meanings, these are problems with collocations. (Common patterns of native speaker usage.)

For the first sentence 'to turn down an opportunity' is the stronger collocation here. (Usually you say 'to miss a chance'.)

For the second sentence 'at the earliest opportunity' is the collocation.

For a good self-study book to improve your awareness and use of collocations, try 'Check Your Vocabulary for Natural English Collocations' by Alison Wooder and Jon Marks.
Amazon.co.uk: Check Your Vocabulary for Natural English Collocations: All You Need to Improve Your Vocabulary (Check Your Vocabulary): Books: Jon Marks,Alison Wooder

Thank you very much for your reply and for your advice.
The problem is you are supposed to use two different words in the above sentences (I didn't say this in my previous post because I didn't want to influence your answer) and as I thought there is no combination which would fit both senteces.
If you use opportunity in the first sentence, you can't use it in the second one. And the same applies to the word chance.

[Clare James]

Then it's the fault of the materials writer then, I think.

If you have to use chance for 'either' of them, then go for the first sentence. But it's not the most natural of expressions. Which book is it taken from?