1. The world has a population of 6.5 billion. / The population of the world is 6.5 billion.
2. noise is harmful to us / our hearing / our health.
(答案不唯一)
1. The world has a population of 6.5 billion. / The population of the world is 6.5 billion.
2. noise is harmful to us / our hearing / our health.
(答案不唯一)