答案解析：

36. graduate
解析：此處需要修飾students的詞。graduate students意為“研究生”。
37. fed
解析：空格前的were表明此處需要動詞、形容詞或分詞，且能與up with搭配。be fed up with意為“受夠了”。
38. owes
解析：此處需要動詞，充當who引導的定語從句的謂語。
39. figure
解析：空格前的trying to表明此處需要填入動詞。figure out意為“弄明白”。
40. track
解析：to表明此處需要動詞，表目的。track作動詞時，意為“追蹤”。
41. credits
解析：此處需要名詞，且能與earn搭配。earn credits意為“賺取信譽”。
42. popular
解析：became表明此處需要形容詞。popular“流行的”。
43. professionals
解析：此處需要名詞復數，與and前的students并列。professionals“專業人士”。
44. 標準答案：It now has about 3,000 users who have made transactions of more than US$875,000
聽音關鍵：3,000 users, transactions, $875,000
答案重構：Now about 3,000 users make transactions of over US$875,000.
畫龍點睛：本句的難點是數字，數字需精確。more than可以用over代替。
45. 標準答案：the amount he/she owes or is owed is shown on the homepage
聽音關鍵：amount, owe, is shown, homepage
畫龍點睛：此處不建議重構，注意he/she owes or is owed是修飾amount的定語從句。聽音時需先抓住主干：the amount is shown on the homepage.
46. 標準答案：as well as the US$1,500 he owes to a friend who bought an airline ticket to India for him
聽音關鍵：$1,500, owes, friend, airline ticket, India
答案重構：and the US$1,500 he owes to a friend for buying an airline ticket to India for him
畫龍點睛：as well as 表示“除……外，也……”。