sole and single

[carat]

Please be so kind and check my sentences in terms of their correctness.Thanks.

There wasn't a mechanic let alone engineer who hasn't had this problem.
There wasn't a sole/single mechanic let alone engineer who hasn't had this problem.
There wasn't a sole/single mechanic let alone engineer who hasn't had this problem before.
There wasn't a sole/single mechanic let alone engineer who hasn't already had this problem before.
There wasn't a sole mechanic let alone engineer who hasn't already had this problem.

 

[GoesStation]

They are all incorrect. Here's one corrected sentence: There wasn't a mechanic, let alone an engineer, who hadn't had this problem.

 

[carat]

So all once again.

There wasn't a mechanic, let alone an engineer, who hasn't had this problem.
There wasn't a sole/single mechanic, let alone an engineer, who hadn't had this problem.
There wasn't a sole/single mechanic, let alone an engineer, who hadn't had this problem before.
There wasn't a sole/single mechanic, let alone an engineer, who hadn't already had this problem before.
There wasn't a sole mechanic, let alone an engineer. who hadn't already had this problem.

There isn't a mechanic, let alone an engineer, who hasn't had this problem.
There isn't a sole/single mechanic, let alone an engineer, who hasn't had this problem.
There isn't a sole/single mechanic, let alone an engineer, who hasn't had this problem before.
There isn't a sole/single mechanic, let alone an engineer, who hasn't already had this problem before.
There isn't a sole mechanic, let alone an engineer, who hasn't already had this problem.

 

[GoesStation]

The first is wrong because the final clause is in the present perfect rather than the past perfect.

The sentences with both already and before are wrong. Use one or the other.

Use single in the others and they're all right. Sole doesn't work in them.

 

[Raymott]

You might be able to use 'sole' in a positive sentence.
"In the huge factory, there was a sole mechanic working."