a shark whistle的用法和样例：
- She entrusted all her saving to a shark.
- The blade of the oar was bitten off by a shark.
- The swimmer's arm was bitten off by a shark.
- He told me he once caught a shark, but I know he was swinging the lead.
- A whale and a shark live in the ocean.
- The ocean is home to a whale and a shark.