A Choose the correct answers. 1 A: How long have you had a toothach B: a For three days. b Since three days. 2 A: Have you been at home all mornin B: a No, I've just arrived. b No, I've already arrived. 3 A: Do you have any science homewo B: a Yes, but I've already done it. b No, I haven't done it yet. 4 A: Is she feeling better? B: a Yes, she's just become sick. b No, she hasn't seen the nurse yet. 5 A: Do you like fruit salad? B: a I've never eaten it. b I've ever eaten it. 6 A: How long have you known Dr Bon B: a For 2012. b Since 2012.

Correct Answers:

1. 1. A: How long have you had a toothache? B: a) For three days. (We use 'for' to indicate a duration of time).
2. 2. A: Have you been at home all morning? B: a) No, I've just arrived. ('Just arrived' implies the arrival is very recent, fitting the context of being asked about the morning).
3. 3. A: Do you have any science homework? B: b) No, I haven't done it yet. (The question asks about possession, and the answer indicates the homework is not yet completed).
4. 4. A: Is she feeling better? B: b) No, she hasn't seen the nurse yet. (This answer directly addresses the question about improvement by stating a reason why she might not be feeling better - not having seen a nurse).
5. 5. A: Do you like fruit salad? B: a) I've never eaten it. (This is a direct and common response to being asked if one likes something one hasn't tried).
6. 6. A: How long have you known Dr Bond? B: b) Since 2012. (We use 'since' to indicate a starting point in time).

Summary: The correct answers were chosen based on standard English grammar and common usage for questions about duration, arrival, completion of tasks, health status, personal experience, and duration of acquaintance.