The correct answers are didn't have and would have adopted.
This is a mixed conditional connecting an ongoing present state to a past result.
We use the past simple (didn't have) for the unreal present/general condition (the lifelong allergy).
We use would have + past participle (would have adopted) for the unreal past result (the missed opportunity yesterday).
Conditional sentence
A conditional sentence describes one situation as depending on another. It pairs a condition clause (usually starting with if) with a consequence clause: If it rains, we'll stay in. The condition can refer to general truths, real future possibilities, hypothetical present situations, or unreal past situations — and each type uses a specific tense pattern.
English teaching groups these into zero, first, second, third, and mixed conditionals. Mastering them lets you talk about plans, regrets, hypotheticals, and warnings — territory you can't reach with simple present and past tenses alone.
Verb tense
Verb tense is the verb form that signals when the action happens. English has three time references — past, present, and future — combined with three aspects (simple, progressive, perfect, plus perfect progressive) to give twelve standard tense forms in total.
Each tense form carries specific meaning beyond just "when". I worked (simple past) and I have worked (present perfect) both refer to past action, but only the second connects that action to the present. Picking the right tense is what makes English narratives clear; the wrong one makes meaning subtly drift.
Past tense
The past tense is how English talks about events finished before now. It comes in four flavours: simple past (I walked) for completed events, past progressive (I was walking) for actions ongoing at a past time, past perfect (I had walked) for events before another past event, and past perfect progressive (I had been walking) for ongoing events leading up to a past point.
Choosing the right one is what makes past narratives clear instead of murky. When I arrived, she ate dinner is technically grammatical but means something different than had eaten (already done) or was eating (in progress when you arrived).
Present tense
The present tense in English has four forms: simple present (I work) for habits, general truths, and stative descriptions; present progressive (I am working) for actions happening right now or temporary situations; present perfect (I have worked) for past actions with present relevance; and present perfect progressive (I have been working) for ongoing actions continuing into the present.
The simple/progressive distinction is one of the trickiest jumps for learners — I work in Paris (habitual) and I'm working in Paris (temporary, right now) feel almost identical but signal different things. Pick wrong and your meaning subtly shifts.
Modal verb
A modal verb is a special class of auxiliary — can, could, may, might, must, shall, should, will, would — that adds shades of meaning around possibility, ability, permission, obligation, or speculation. I can swim (ability), You should rest (advice), It might rain (possibility), You must leave (obligation).
Modals are grammatically peculiar: no -s in the third person (she can, not she cans), no infinitive, no participle, followed by the bare verb (I can swim, never I can to swim). Mastering them is the move from describing facts to expressing how you feel about them — likelihood, necessity, recommendation.
B2 | Upper Intermediate
B2 is the upper-intermediate level in the CEFR framework, sitting between B1 and C1. At B2 you can read editorials, follow most TED talks without subtitles, and hold extended conversations on abstract topics — including topics outside your everyday life.
Grammatically, B2 means flexible control of mixed conditionals, passive voice across tenses, reported speech with proper backshifting, and participle clauses. B2 is the standard target for university entrance exams (IELTS 5.5–6.5, TOEFL 87–109) and most skilled-migration thresholds — knowing whether you're there shapes your study plan.
Difficulty: Hard
The Hard difficulty tag marks questions and challenges aimed at upper-intermediate to advanced learners — typically B2 and above. Expect interacting rules, edge cases, distractors that look right at first glance, and contexts where the surface meaning and the grammatical answer don't match.
Filter by Hard when you're past the basics and want material that genuinely tests your understanding. These questions catch the gaps your textbook didn't — register-sensitive choices, exception cases, mixed conditionals, the difference between would have been and had been.