1a. Make the questions more polite.
• Use "Do you know / Can you tell me...
Example: Where is Max? (Do...) - Do you know where Max is?
1. How did the solve it? (Do...)
2. Why does Alex suspect them? (Can...)
3. What exploded in the air? (Do...)
4. Who stole the gold bracelet? (Can...)

Do you know how to solve it?Can you tell me why alex suspects them?Do you know what exploded in the air?Can you tell me who stole the golden bracelet?