国际上主流的3G标准有三个:即(),欧洲标准;(),美国标准;(),中国提出的标准。
参考答案:WCDMA;CDMA2000;TD-SCDMA
按要求完成下列句子。
1. She's never been to Tokyo. (改为反意疑问句)
She's never been to Tokyo, ______ ______?
2. It'll be sunny tomorrow. (改为反意疑问句)
It'll be sunny tomorrow, ______ ______?
3. The boys were having a math class at this time yesterday. (改为反意疑问句)
The boys were having a math class at this time yesterday, ______ ______?
4. Go across the bridge, and you'll see the hospital. (改为同义句)
______ the______, and you'll see the hospital.
5. This book cost Peter 5 yuan. (改为同义句)
Peter ______ 5 yuan ______ this book.
月掩星、凌日等天象能发生,是因为行星、月球的公转轨道平面彼此偏角很小。