翻译：你必须到18岁才被允许开车

你必须到18岁才被允许开车
You are not allowed to drive until you reach 18.

我不知道选择哪一条牛仔裤，这两条我穿上都合适。
I don't know which pair of jeans to buy ,both of them fit me very well.

牛仔裤是jeans，楼上的不够口语。

You can't drive until you are 18.

I don't know which pair of jeans to pick，they are both my size.

you are not allow to drive untill you are 18.

I don't know which pair of jeans to buy, both of them go with me!

You're not allowed to drive a car until you are 18.
I have no idea to choose which trousers,these two both are fit me.