37. What __ the children eat for lunch yesterday? 38. __ she call you last night? 39. __ the students prepare for their exams properly? 40. Who __ she meet at the party last night? 41. __ your brother play football yesterday afternoon? 42. Where __ he park his car this morning? 43. When __ they visit their relatives in the village? 44. How __ he solve the math problem? 45. __ the baby cry all night yesterday? 46. __ your boss give you a day off last week? 47. Why __ the plane delay its flight? 48. What __ they talk about during the meeting? 49. __ you enjoy the book you borrowed from the library? 50. __ the manager inform the team about the changes?

These questions are all asking for the correct auxiliary verb to complete a question in the past simple tense. Here are the answers:37. **What did** the children eat for lunch yesterday?38. **Did** she call you last night?39. **Did** the students prepare for their exams properly?40. Who **did** she meet at the party last night?41. **Did** your brother play football yesterday afternoon?42. Where **did** he park his car this morning?43. When **did** they visit their relatives in the village?44. How **did** he solve the math problem?45. **Did** the baby cry all night yesterday?46. **Did** your boss give you a day off last week?47. Why **was** the plane delay its flight? (Note: This requires "was" because "delay" is a singular noun.)48. What **did** they talk about during the meeting?49. **Did** you enjoy the book you borrowed from the library?50. **Did** the manager inform the team about the changes?The key is understanding that the past simple tense in questions uses the auxiliary verb "did" (for most verbs) or "was/were" (for the verb "to be"). "Did" is used with the base form of the main verb.