THE (NOT, A)

English for Today by Ganiu Abisoye Bamgbose (Dr GAB)

THE (NOT, A)

The number of failure could be just ~a~ tip of the iceberg (nonstandard).
The number of failure could be just the tip of the iceberg (standard). If you say that a problem is the tip of the iceberg, you mean that it is one small part of a much larger problem. This implies that the expression is used in negative situations.

Even in her sixties, she is still ~an~ epitome of elegance and beauty (nonstandard).
Even in her sixties, she is still the epitome of of elegance and beauty (standard).

At first, I gave him the benefit of doubt (nonstandard).
At first, I gave him the benefit of ~a~ doubt (nonstandard).
At first, I gave him the benefit of the doubt (standard).
GAB