 Re: Adverb or not?
You've raised a different issue here - that of variety of English. You said that the learners were taking an EAP course, so this is presumably medical English - which may well have different characteristics from other varieties.
If this were not medical English but just eg an article on allergies in a magazine fast would be fine as a collocation with disappear. Here are some authentic examples :
... the money was disappearing as fast as we replenished it
The strength in the US Dollar, an illusion revealed by the global strength in gold, will disappear as fast as it materialized
The white sandy beaches could disappear as fast as the reefs.
and even...
... allergy can disappear as fast as it emerges
Make Your Allergies Disappear Fast
When I checked a medical English corpus however, I couldn't find any examples of fast used as an adverb, though there were a lot for the comparative, faster, eg :
..with liquids emptying faster than normal and solids being retained in the stomach
incidence and mortality of prostate cancer are increasing faster than can be attributed simply to ...
Gallo noted that virus replicated faster in an activated cell where deoxyribonucleotides
There were a number of examples of quickly. Looking at the examples reporting research (as opposed to medical management) it was clear that the adverb is often used to premodify rather than postmodify the verb it relates to - eg :
This needs emphasising to patients, as some on diet alone quickly learn that ...
rather than "learn quickly that"...
Some other examples :
HBV - DNA disappeared from the serum but quickly reappeared after discontinuation of therapy,
...muscular tissue layers were then separated by quickly pulling the two slides apart.
The preference of to premodify rather than postmodify is common in more formal varieties of English and can at least partially explain why fast is not used : fast can only postmodify and therefore would be grammatically impossible here.
It doesn't explain though why it would not be used in an as...as construction, as in the original example. However, even with quickly, there are only two examples in the whole of the 1.4 million word corpus, so it could be just chance.
I suspect that another reason for the preference for quickly is that, when used as an adverb of manner, fast sometimes has a connotation of urgency. Compare for example :
You need to decide fast/quickly
Fast (to me at least) here conveys a rather dramatic tone which would be out of place in a medical paper, or in academic style in general, and therefore quickly might well be preferred.
The advice to always use quickly would sometimes work It's often an alternative and is sometimes the most likely choice even in general purpose English - eg in
The girl looked around quickly at several of the people.
.. half a minute later a cloaked figure came quickly out of the Garden Tower's entrance .
However, it could also lead the students into error. There are a lot of situations where they are not alternatives : eg fast rather than quickly is generally used to modify a present participle and create a compound adjective - eg a fast-approaching deadline / the already fast-declining living standards of the population.
At an advanced level (which I presume your students are, if they're studying EAP), it is aspects such as connotation, collocation, and syntactic choice connected with specific varieties of English that the students need to know. Basic definitions of meaning and "play safe" rules (which can be very useful at lower levels) are no longer enough. |