Read the sentences and choose the correct answers

Which silent letters do the words in bold have?

Who do you want to be when you grow up? [ ]

1. Which
   book is your favourite?
   [W|H|K].
2. I like going to the
   buffet
   at my lunchtime.
   [B|H|T].
3. Knowledge
   is a key to success.
   [K|W|T].
4. If you like my video, put
   thumbs
   up.
   [T|H|B].