Exercise 3: Choose the best option to complete the sentence. ​1.​ are you doing? - I’m reading a book.
​A. Whom​B. Who​C. Whose​D. What
​2.​ coffee is this? – It’s mine.
​A. Who​B. Which​C. Whose​D. What
​3.​ of these problems are you most interested in?
​A. Who​B. Whom​C. Which​D. What
​4.​ do you know about this subject, and who taught it to you?
​A. Which​B. Who​C. What​D. Whom

​5.​ is responsible for the accident?
​A. Whose​B. Who​C. Which​D. Whom
​6.​ children are they? - The Browns’.
​A. Whose​B. Which​C. Whom​D. Who
​7.​ doesn’t understand what the teacher has explained?
​A. Which​B. Whose​C. Who​D. What
​8.​ is the weather like today?
​A. What​b. Who​C. Which​D. Whose
​9.​ the longest river in the world: the Amazon or the Nile?
​A. Whom​B. What​C. Who​D. Which
​10.​With did you go to the seaside?
​A. who​B. whom​C. what​D. which