Focusing adverbs

The focusing adverb (e.g. merely, only, etc.) stresses one item of information contained in a sentence.

It is usually placed between the subject and verb:

I merel y wrote to Susan.

I only wrote to David.

However, if another item is to be stressed, the focusing adverb is usually put before the item emphasized as in:

I only wrote to David yesterday. (i.e. “I did nothing else”)

I wrote only to David yesterday. (i.e. “to no one else”)

I wrote to David only yesterday. (“yesterday and no other day or as late as yesterday”).

or the focusing adverb is placed after the item emphasized:

I wrote to David yesterda y only.

Can you buy a car on your salary alone?

Note, that alone always follows the item emphasized.