The correct answer is "had". This is a second conditional sentence about an unreal present situation. If I had more time now, then I would learn another language.

The correct answer is "has lived". The phrase since 2010 requires the present perfect tense has lived to indicate an action that started in the past and continues to the present.

The correct answer is "had started". The past perfect tense is used for an action that was completed before another past action by the time we arrived.

The correct answer is "going". The verb suggested is followed by a gerund the ing form. He suggested going to the cinema.

The correct answer is "were". After I wish, the subjunctive mood uses were for all persons when expressing an unreal wish.

The correct answer is "was he". Inversion is used with not only at the beginning of a sentence. Not only was he late, but also...

The correct answer is "waking up". The phrase get used to is followed by a gerund the ing form. She can't get used to waking up early.

The correct answer is "had studied". This is a third conditional sentence: if plus past perfect had studied, then would have passed.

The correct answer is "told". After I'd rather you, the past tense told is used to express a preference about someone else action.

The correct answer is "had I arrived". Inversion with hardly requires the past perfect and subject-verb inversion. Hardly had I arrived when...

The correct answer is "taking". The verb denied is followed by a gerund the ing form. She denied taking the money.

The correct answer is "had we left". Inversion with no sooner requires the past perfect and subject-verb inversion. No sooner had we left than...

The correct answer is "working". The phrase is used to is followed by a gerund. He is used to working long hours means he is accustomed to it.

The correct answer is "saying". The verb regret can be followed by a gerund to refer to a past action that you wish had not happened.

The correct answer is "will have been completed". By next month refers to a future time, so the future perfect passive is required.

The correct answer is "did". The phrase It's high time is followed by the past simple tense to express that something should be done now.

The correct answer is "would have left". This is an inverted third conditional sentence. Had I known means If I had known, then would have left.

The correct answer is "paying". The verb insisted on is followed by a gerund the ing form. She insisted on paying the bill.

The correct answer is "have I seen". Inversion with rarely at the beginning requires the auxiliary before the subject. Rarely have I seen such a beautiful sight.

The correct answer is "stay". After would rather, the base form of the verb is used when the subject is the same. He would rather stay at home.