XDF蓝皮书PART2 49

　　Two week notice being given to employers before leaving a job is the generally accepted protocol.

• Two week notice being given to employers before leaving
• Giving notice to employers of two weeks before having to leave
• Two week's notice to give to employers before leaving
• Giving notice to employers two weeks before leaving
• To give two week's worth of notice before having to leave

答案是D，是通过排除法，

问题是：doing sth. is sth.　这个结构正确吗，看的别扭，好像做过一题说这个结构不正确．