a causal relationship的用法和样例：
- A causal relationship between scarcity of goods and higher prices.
- Transfers create a causal relationship between activities within endpoints.
- The book traced a causal relationship between the rate of monetary growth andthe price level.
- The book traced a causal relationship between the rate of monetary growth and the price level.
- The author regards human and state as two nouns with a causal relationship which reveals the possibility and necessity of the birth of Leviathan.