What is the difference between "only for as long as" and "only if"?
- A coral reef will continues to exist only for as long as it can expand at a faster rate than it is being destroyed.
- Annual subscription options allow you to commit to a contract only for as long as you need it.
- Children are admitted only if accompanied by an adult.
- The lawyer is paid only if he wins.
I am learning toward "only for as long as". It seems like that there is no difference between "only for as long as" and "only if". Is it right? If so, which one is more well-used expression?
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