[单选题]You can use my car（ ）you promise to be back before lunch.
A
as far as
B
as long as
C
as well as
D
as much as
正确答案：B
题目解析
本题考查关于as的连词辨析。as far as：就…而言，直到…为止；as long as：只要；as well as：除…之外（也）；as much as：(置于数量前)多达。分析前后两个分句可知，前半句是后半句的条件，所以选择B选项带入语境最为合适。
句意：只要你答应午饭前回来，你就可以用我的车。
