Only is a capricious word. It is much given to deserting its post and taking its place next the verb, regardless of what it qualifies. It is more natural to say 'he only spoke for ten minutes' than 'he spoke for only ten minutes'. ... But it cannot be denied that the irresponsible behaviour of only does sometimes create real ambiguity. Take such a sentence as:

His disease can only be alleviated by a surgical operation.

We cannot tell what this means, and must rewrite it either:

Only a surgical operation can alleviate his disease (it cannot be alleviated in any other way).


A surgical operation can only alleviate his disease (it cannot cure it).

The Complete Plain Words, 2nd edn. 1973

I tapped you on your arm with my stick yesterday.

Stress can be used to resolve some potential ambiguity.