1. A painter is drawing John's portrait.
Answer: John is having his portrait drawn.
Explanation: This sentence uses the causative form 'have something done'. The focus is on John causing someone else to draw his portrait.
2. An architect from London has designed my flat in Moscow.
Answer: I had my flat in Moscow designed by an architect from London.
Explanation: The speaker is emphasizing that they caused the flat design to happen, and an architect from London did it.
3. My father will fix my bike.
Answer: I will have my bike fixed by my father.
Explanation: Indicates that you are getting your father to do the fixing of the bike for you.
4. A hospital doctor examined Jennifer yesterday.
Answer: Jennifer had herself examined yesterday.
Explanation: Emphasizes Jennifer caused to examine.