Hay muchos visitantes en el museo - There are a lot of visitors in the museum.
Siglo - century (doesn't match with the sentence)
Exposiciones - expositions (feminine, does not fit in the sentence)
Visitantes - visitors (masculine and makes sense)
Hope it helped,
Happy homework/ study/ exam!
37. hablarán
38. pudiera
39. sabía
40.entendiera
41.recomenzaban
42. tuviera
43. parara
44.bailará
45. quería