English grammar error-spotting (natural collocation: ‘‘catch a cold’’ not ‘‘get a cold’’ in tests): Read the sentence fragments (A–D) and mark the single erroneous part. Sentence: ‘‘When I get a cold / it takes me weeks / to shake it off. / No error.’

ExplanationAlthough ‘‘get a cold’’ occurs in informal speech, many competitive-exam keys prefer the idiom ‘‘catch a cold’’ for accuracy in standard usage. Everything else is correct (present simple for habitual truth, infinitival purpose phrase).

Correction‘‘When I catch a cold, it takes me weeks to shake it off.’’

Common pitfalls

• Using colloquial variants where exams expect the canonical idiom (catch a cold).

Final AnswerWhen I get a cold