完成式的三個簡單問題 - 籃球

寫書的時候看到以下三句 覺得兩個答案都可以
這題自從他九歲就在打籃球了 有可能現在不打了嗎 答案是否一定為1呢
She has played basketball since she was 9 years old.
Q: Does she still play basketball?
1.Yes(She plays sometimes.)
2.No(She never plays anymore.)
這提示說那女生住L:A兩個月了 答案是一嗎 為什麼
Jean has lived in LA for two months.
Q: Does Jean still live in LA?
1.Yes (The action is continuing.)
2.No(The action is finished.)
這題答案是一對吧 想要make sure一下
They have always watched TV on Saturdays.
Q: Do they still watch TV on Saturdays?
1.Yes
2.No
請問完成式的使用時機還有情況是什麼
有表示以後會持續下去的意思嗎?? 希望可以講清楚一點 謝謝