The last time I ate sushi was the last summer

1. The last time I ate sushi was the last summer.
A. I have eaten sushi since the last summer,
B. I haven't eaten sushi since the last summer.
2. I last saw her on Monday.
A. I haven't seen her since Monday.
B. I have seen her since Monday.
3. I haven't watered this tree for a week.
A. The last time i watered this tree was a week ago.
B. The last time I didn't water this tree was a week ago.
4. I started collecting stamps last winter.
A. I have collected stamps since last summer.
B. I have started collecting stamps since last summer.
5. How long have you worked as a volunteer?
A. When did you start working as a volunteer?
B. When have you worked as a volunteer?
6. This singer's last performance was in Jly 20th.
A. This singer has performed since July 20th.
B. This singer hasn't performed since July 20th.
7. They began playing tennis in the spring of 2012.
A. They have played tennis since the spring of 2012.
B. They haven't played tennis since the spring of 2012.
8. I last went to the zoo when I was 10.
A. I haven't gone to the zoo since I was 10.
B. I have gone to the zoo since I was 10.
ing as the first.