35. A - "wasn't" should be "hasn't been" to correctly use the present perfect tense.
36. B - "hers" should be "her" to correctly use the possessive adjective.
37. A - "went" should be "to go" to correctly use the infinitive form after "how."

Corrected sentences:
35. Bob hasn't been (A) out of his house (B) since he was given (C) a (D) new computer.
36. I'm not surprised (A) she failed her (B) exam as he didn't exactly (C) try very hard (D)!
37. Ms Lan didn't know how to go (A) to the party yesterday because (B) her (C) bike broke down (D).