Ответ:

Part 3  

Use of English  

Task 1 .  

37 - to, 38 - V, 39 - which/ that, 40 - the, 41 - on, 42 - a/ the, 43 - to, 44 - V,

45 - of, 46 - their/ the,  47 - the,  48 - V,   49 - because.