Grammar Flashcards

Choose the option that correctly completes the sentence: "Not until the final results were published ___ how badly the experiment had failed."

Answer: did the researchers realise

When a sentence starts with the negative phrase 'Not until...', the main clause needs subject–auxiliary inversion: auxiliary + subject + main verb. In the past simple, the auxiliary is 'did', which gives 'did the researchers realise'. Normal word order ('the researchers realised') and emphatic 'did' without inversion are both wrong. 'Had realised the researchers' puts the whole verb before the subject, which English does not allow here.

Choose the correct option: "If she hadn't turned down that job offer last year, she ___ in Singapore now."

Answer: would be living

This is a mixed conditional. The if-clause describes an unreal past event ('hadn't turned down... last year'), and the result clause describes an unreal present situation ('now'). An unreal present result takes 'would' + infinitive, and here the continuous form fits: 'would be living'. 'Would have lived' would refer to a past result and clashes with 'now'. 'Will be living' is a real future form, and 'had been living' is not a result-clause form.

Choose the most grammatically appropriate option for formal written English: "It is essential that every applicant ___ the declaration in person."

Answer: sign

Adjectives of necessity or importance, such as 'essential', 'vital' and 'crucial', followed by a that-clause take the mandative subjunctive. That is the bare infinitive, used for every subject, so we write 'every applicant sign' with no -s. The past form 'signed' and the indicative forms 'will sign' and 'has signed' do not express the required obligation in this formal structure.

Choose the correct option: "Hardly ___ the platform when the train pulled out of the station."

Answer: had we reached

'Hardly... when' describes one past event happening immediately after another. The earlier event takes the past perfect. Because 'Hardly' is a negative adverb at the start of the sentence, the subject and auxiliary must be inverted: 'Hardly had we reached...'. Options without inversion are wrong, and 'have we reached' uses the wrong tense for a past sequence.

Choose the correct option: "___ in 1998, the suspension bridge is now in urgent need of structural repair."

Answer: Built

The subject of the main clause, 'the bridge', received the action: someone built it. That calls for a passive participle clause. 'Built in 1998' is a reduced form of 'Having been built in 1998' / 'which was built in 1998'. 'Building' is active, which would mean the bridge built something. 'Being built' suggests the construction is still in progress, which contradicts 'in 1998'. 'Having building' is not a grammatical form.

Choose the option that best completes the sentence: "You ___ brought an umbrella — it didn't rain all day, so carrying it around was completely pointless."

Answer: needn't have

'Needn't have' + past participle describes something that was actually done but turned out to be unnecessary, which is exactly the situation here: the umbrella was brought and wasn't needed. 'Mustn't have' is not standard for past deduction ('can't have' is used instead) and doesn't express lack of necessity. 'Couldn't have' expresses impossibility. 'Didn't need to' is followed by a bare infinitive ('didn't need to bring'), not 'have' + participle, and it usually implies the action wasn't done.