Position of Adverbs
Authorities, including H. W. Fowler (A Dictionary of Modern English Usage, 1926) and B. A. Garner (A Dictionary of Modern American Usage, 1998), vigorously reject two widely accepted "rules" regarding adverb position. These unsupported rules are Do not split an infinitive with an adverb and Do not split a compound verb with an adverb.
Which of the following sounds more natural, less awkward?
(a) To reproducibly extract DNA from soil, one must account for organic matter.
(b) To extract DNA from soil reproducibly, one must account for organic matter.
Split the infinitive!
But you might decide to leave the infinitive unsplit if your boss believes in the rule and will fire you if you break it (good writers and other conscious beings must often chose between what is right and what is expedient).
You might also decide that both forms, split and unsplit, sound awkward, in which case you should find another way to express the thought.
Splitting compound verbs
Compound verbs are those that include the main verb form and an auxiliary verb. In the following sentence the compound verb is were examined (the main verb form is examined and the auxiliary verb is were):
The extracted nematodes were examined.
We can add the adverb also in two places.
(a) The extracted nematodes were also examined.
(b) The extracted nematodes also were examined.
Neither of these is wrong, but in a recent paper I used (a) because it sounded better to me. Both Fowler and Garner apparently agree. They state that the preferred position for the adverb is after the auxiliary verb. In other words, Fowler and Garner recommend that we split the compound verb unless we have good reason not to. Note that in preparing my paper for publication, the journal editor changed my sentence (a) to (b), but I changed it back to (a) on the proof - the principle is that authors should not be forced to accept meaningless changes. A second principle is that editors and technical editors sometimes learn silly rules.
Here is another example from the same paper: I wrote:
(c) The assay organism should ideally have the following characteristics.
The technical editor changed this to:
(d) The assay organism ideally should have the following characteristics.
Again, I changed it back to (c) because (c) seemed more natural to my ear.