The past participle of wreak is wreaked, as in boll weevils wreaked havoc on the US cotton industry. An alternative expression is wrought havoc, as in over-fishing has wrought havoc in some areas. Wrought is an archaic past tense of work and is not, as is sometimes assumed, a past tense of wreak. There is therefore no justification for the view, sometimes expressed, that wreaked is an incorrect form.
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In its emphatic use (e.g. whenever shall we arrive?) the one – word form whenever may also be written as two words (whenever shall we arrive?). In its other senses , however, it must be written as one word: you can ask for help whenever you need it; I’ll do it at the weekend or whenever.
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Some people claim that the true sense of the adjective verbal is ‘of or concerned with words’, whether spoken or written (as in verbal abuse), and that it should not be used to mean ‘spoken rather than written’ (as in a verbal agreement). For this meaning it is said that the adjective oral should be used instead. In practice, however, verbal is well established in this sense and in certain idiomatic phrases (such as a verbal agreement) cannot be simply replaced by oral.
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Logically, the verb unthaw should mean ‘freeze’, but in North America it means exactly the same as thaw (as in the warm weather helped unthaw the rail lines); because of the risk of confusion it is not part of standard usage. Unthawed as an adjective always means ‘still frozen’, but it is best avoidable because many contexts may be ambiguous.
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When the adjective worthwhile is used before the noun. (i.e. attributively) it is always written as one word: a worthwhile cause. However, when it stands alone and comes after the verb (i.e. when used predicatively) it may written as either one or two words: we didn’t think it was worthwhile or we didn’t think it was worth while.
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