我问一道英语题

搞不清你的意图，提供以下几个供选择：
1. I start at seven. I don't arrive at half past eight.
我七点出发。我八点半到达不了
2. I have to start at seven, or I don't arrive at half past eight.
我必须七点出发，否则我八点半到达不了。
3. If I don't start at seven，I don't arrive at half past eight.
如果我不在七点出发，八点半就到达不了。
4. Though I start at seven，I don't arrive at half past eight.
尽管我七点出发，八点半也到达不了。