$11.$ If I were free, I would go with you tonight.
$12.$ If she had been able to answer the questions, she wouldn't have failed the exam.
$13.$ If Peter hadn't been nervous, he wouldn't have failed the driving test.
$14.$ If I had had a watch, I could have told you what time it is.
$15.$ If she had learnt Maths, she wouldn't have been cheated by that salesman.
$16.$ If the clock had been right, we wouldn't have missed the train.
$17.$ If the dress hadn't been very expensive, she could have bought it.
$18.$ If the pupils hadn't done their homework carelessly, the teacher wouldn't have been very angry.
$19.$ If I didn't have lots of good friends, I would feel lonely.
$20.$ If we had had enough time, we could have gone on holiday.
$21.$ If we had had a map, we wouldn't have got lost.