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The word "perfect" in this sense means "completed"; it contrasts with the "imperfect", which denotes uncompleted actions or states. In English grammar, the pluperfect (e.g. "had written") is now usually called the past perfect, since it combines past tense with perfect aspect. (The same term is sometimes used in relation to the grammar of other ...
The past perfect progressive or past perfect continuous (also known as the pluperfect progressive or pluperfect continuous) combines perfect progressive aspect with past tense. It is formed by combining had (the past tense of auxiliary have), been (the past participle of be), and the present participle of the main verb.
It can be proven that: . For a given prime number p, if n is p-perfect and p does not divide n, then pn is (p + 1)-perfect.This implies that an integer n is a 3-perfect number divisible by 2 but not by 4, if and only if n/2 is an odd perfect number, of which none are known.
Illustration of the perfect number status of the number 6. In number theory, a perfect number is a positive integer that is equal to the sum of its positive proper divisors, that is, divisors excluding the number itself. [1] For instance, 6 has proper divisors 1, 2 and 3, and 1 + 2 + 3 = 6, so 6 is a perfect number.
Resultative perfect (referring to a state in the present which is the result or endpoint of an event in the past): "I have lost my pen-knife" (message: I still don't have it) Continuative perfect (past situations continuing into present): "I have always guided him" Anterior perfect (completed past situations, but with relevance to the present):
For example, 3 is a Mersenne prime as it is a prime number and is expressible as 2 2 − 1. [ 1 ] [ 2 ] The exponents p corresponding to Mersenne primes must themselves be prime, although the vast majority of primes p do not lead to Mersenne primes—for example, 2 11 − 1 = 2047 = 23 × 89 .
The base form or plain form of an English verb is not marked by any inflectional ending.. Certain derivational suffixes are frequently used to form verbs, such as -en (sharpen), -ate (formulate), -fy (electrify), and -ise/ize (realise/realize), but verbs with those suffixes are nonetheless considered to be base-form verbs.
The past perfect progressive (sometimes referred to as the past perfect continuous) combines had (the simple past of have) with been (the past participle of be) and the present participle of the main verb: You had been waiting. It is used to refer to an ongoing action that continued up to the past time of reference.