怪不得

guàibude
  1. no wonder!
  2. so that's why!

CEDICT

Entry Composition

=1 怪 guài
  1. bewildering
  2. odd
  3. strange
  4. uncanny
  5. devil
  6. monster
  7. to wonder at
  8. to blame
  9. quite
  10. rather
=1 怪 guài variant of 怪 guài
2 不得 bùdé
  1. must not
  2. may not
  3. not to be allowed
  4. cannot