How many types of oxygen molecules makes up ozone?
举一反三
- How do you understand the remark “It’s not how many times you fall down that matters. It’s how many times you get back up that makes success!”?
- 中国大学MOOC: Water i________ a liquid made up of molecules of hydrogen and oxygen in the ratio of 2 to 1.
- How many types of friends ?
- How many types of pollution are there?what are they ?
- How many types of tourism are there in China?