如果你想要从你的舍友那里索要车费，你可以这样说：

"Hey, could you give me the money for the ride we took last week? I'm a pttle short on cash right now."

"Hi, do you remember when we carpooled to the store last week? I was wondering if you could pay me back for my share of the gas."

"Hey, I'm just wondering if you could pay me back for the ride I gave you last week. It would really help me out."

请注意，在英语中，索要车费通常称为"paying back"或"reimbursing"费用。