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influenced by conjugation (as with ketones) carboxylic acids/derivates saturated carboxylic acids 1710 unsat./aromatic carb. acids 1680–1690 esters and lactones: 1735 influenced by conjugation and ring size (as with ketones) anhydrides 1760 1820 acyl halides: 1800 amides: 1650 associated amides carboxylates (salts) 1550–1610 amino acid ...
Conjugation is the variation in the endings of verbs (inflections) depending on the person (I, you, we, etc), tense (present, future, etc.) and mood (indicative, imperative, subjunctive, etc.). Most French verbs are regular and their inflections can be entirely determined by their infinitive form.
The "stemless" verb ir belongs to this group, with yendo. For -er and -ir verbs whose stem ends in ñ or ll , the -iendo ending is reduced to -endo: tañer → tañendo, bullir → bullendo. [4] The gerund has a variety of uses and can mean (with haciendo, for example) "doing/while doing/by doing/because of one's doing/through doing" and so on.
Though the list of verbs irregular in the preterite or past participle is long, the list of irregular present tense verbs is very short. Excepting modal verbs like "shall", "will", and "can" that do not inflect at all in the present tense, there are only four of them, not counting compounds including them:
Old Norse has three categories of verbs (strong, weak, & present-preterite) and two categories of nouns (strong, weak). Conjugation and declension are carried out by a mix of inflection and two nonconcatenative morphological processes: umlaut, a backness-based alteration to the root vowel; and ablaut, a replacement of the root vowel, in verbs.
Differences between the past tense and past participle (as in sing–sang–sung, rise–rose–risen) generally appear in the case of verbs that continue the strong conjugation, or in a few cases weak verbs that have acquired strong-type forms by analogy – as with show (regular past tense showed, strong-type past participle shown).
The table at the right shows the main verb forms, with examples for -ar, -er and -ir verbs (based on parlar 'to speak', vider 'to see', and audir 'to hear'). The simple past, future, and conditional tenses correspond to semantically identical compound tenses (composed of auxiliary verbs plus infinitives or past participles).
Woodward's rules, named after Robert Burns Woodward and also known as Woodward–Fieser rules (for Louis Fieser) are several sets of empirically derived rules which attempt to predict the wavelength of the absorption maximum (λ max) in an ultraviolet–visible spectrum of a given compound.