English World Mistakes

Grammar Practice Book. Level 2

1. It should be c, not d. This one is obvious, if you look at the options.
2. It should be Whom, not Who. This one needs to be explained, because this is a mistake even native speakers of English make. So, what's the difference?
   
   Who  is a subject (can be mentally substituted by he), and whom is an object (can be mentally substituted by  him). The final m in whom and him will help you use who and whom correctly.