B. will have been collecting
("Hoa will have been collecting coins and stamps for ten years by the end of this year" is the correct form because it refers to an action that will be ongoing for a period of time up until a future point.)

C. isn’t he
("He thinks the boy is teasing him, isn’t he?" is the correct tag question because the main sentence is affirmative, so the tag question should be negative.)

A. drive
("Do you mind if I drive your car to work?" uses the base form of the verb "drive" after "if I" in a question.)

B. had never done
("I really regret telling lies to my mom. I wish I had never done that." is the correct past perfect form for expressing regret about something in the past.)

C. breaking
("My sister regretted breaking Mai’s glasses yesterday." uses the gerund "breaking" after "regretted.")

A. is
("One hundred dollars is a big amount of money for her." uses the singular form "is" because "one hundred dollars" is considered a singular amount.)

D. whose
("The boys whose mom is a teacher was suspended yesterday." uses "whose" to indicate possession.)

A. had finished
("If you had finished your work before, we would be able to go out now." is the correct third conditional form, expressing an unreal past situation.)

B. must have caught
("Lily is late again. She must have caught the wrong bus." uses "must have caught" to suggest a likely reason for something that has already happened.)

C. neither
("Nam and Manh have played badminton for two hours, but neither of them are tired." uses "neither" because it refers to two people and expresses that neither one is tired.)