You can also say If Patrick had looked in the mirror before reversing the car, he would have seen the wall. (But he didn't. Oops.) This is a subjunctive sentence, without if. In the first clause, you put the auxiliary verb before the subject, Had Patrick, and then the rest of the sentence stays the same. The second part is a normal clause where the verbs follow the subject he would have seen.
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.
Inversion
Inversion is reversing the normal English word order of subject + verb. The everyday case is subject–auxiliary inversion for questions: Sam has read it → Has Sam read it?. The more advanced case is inversion after fronted negative or restrictive expressions: Rarely have I seen such dedication / Not only does she sing, she also writes.
The advanced kind is a hallmark of formal and literary English — used after openers like never, seldom, not until, only when, little did I know. Mastering it is a C1+ skill that signals careful, register-appropriate writing.
C1 | Advanced
C1 is the advanced level in the CEFR framework, sitting between B2 and C2. At C1 you stop translating in your head and start thinking in English — handling specialised articles outside your field, picking up implicit meaning, and writing structured arguments on complex topics.
Grammatically, C1 means natural use of inversion (Rarely have I seen…), mixed and advanced conditionals, subjunctive forms in formal contexts, and cleft sentences for emphasis. Most university programmes for non-native speakers and many professional certifications set C1 as their entry standard.
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.