The concept for wireless electrical transduction was proposed about _______ years ago by _______.
举一反三
- When was the man in New York A: About two years ago. B: About one year ago, C: About three years ago.
- Many years ago he hadwriting a book about his childhood.
- It was about 600 years ago （） the first clockwith a face and an hour hand was made.
- These dolls represent a royal family in Japan about ________years ago, in Heian period.
- More than two ______ years ago, people knew little about the universe.