下列各组句子中加横线字的意义和用法完全相同的一组是（ ）

下列各句中，表达得体的一项是

Would you like to attend China’s Got Talent (中国达人秀)—- ______ But I’m busy revising for my test.

Let’s go climbing, shall we–You _______ be joking! Don’t you know I’m afraid of high places

k it unwise to live ______ one’s income,as is the case with a lot of young people today, who often turn to theirparents for help