Bonjour,
Réponse :
17. What did (A) you use to wear when you were young?
( Phrase interrogative au prétérit, auxiliaire "did" )
18. Did they use to ( D ) go to the cinema?
( Phrase interrogative au prétérit le verbe n'est pas conjugué )
19. I didn’t use to (A) play
( Phrase négative au prétérit, le verbe n'est pas conjugué )
20. My travel bag is lighter ( B) than yours.
( Comparatif de supériorité de "light" -> "lighter" ( plus léger ))
21. Who has the easiest ( C ) job in your family?
( Superlatif de "easy" -> "easiest" )
22. I think studying mathematics is more difficult ( C ) than learning English.
( Comparatif de superiorité de difficult -> "more difficult" )
23. My brother has ( B ) eaten my cakes.
( présent perfect 3ème personne du singulier: has + participe passé )
24. We have been working ( B ) for 8 hours.
( présent perfect progressif. 1ère personne du pluriel : have been + BV-ing )
25. They have prepared ( A ) a lot of food recently.
( présent perfect : l'indice est "recently" )
26. The boys have given ( A ) many problems.
( présent perfect 3ème personne pluriel : have + participe passé )
27. Do you think physics is more useful ( C ) than chemistry?
( Comparatif de supériorité de "useful" -> " more useful"
28. He is the best ( C ) at math.
( Superlatif de good -> "the best" ( le meilleur )
29. This story is the most interesting ( D ) I have ever heard.
( superlatif adjectif long "interesting" -> "the most interesting" )
30. The sun is the furthest ( C ) planet from Earth.
( superlatif de far -> "the furthest" ( la plus éloignée ))
31. The instructor told us: « Hold position for 10 seconds »
==>( B ) The instructor told us to hold position for 10 seconds.
( passage du discours direct au discours indirect d'une phrase impérative, on utilise l'infinitif )
32. They said: « We are going ice-skating. »
==> ( D) They said that they were going ice-skating.
( Passage du discours direct au discours indirect, le présent devient prétérit. Et changement de pronom )
Explications :
Mes explications sont succintes, il et difficile de mettre toutes les règles.
N'hésite pas si tu as des questions.
;)