在3G的三种技术中,WCDMA和CDMA2000采用频分双工方式。需要成对的频率规划。
参考答案:对
阅读Sam上周活的短文,根据短文内容选择正确答案。
On Monday, Sam played football. On Tuesday, Sam listened to music. OnWednesday, he watched TV. On Thursday, he helped his mother with the housework. On Friday, he washed his clothes. On Saturday,
he did his homework. On Sunday, he played the guitar.
1. On Saturday, Sam .
A. talked to his friends
B. did his homework
2. On Monday, Sam _ .
A. played football
B. played basketball
3. On Friday, Sam .
A. read a book
B. washed his clothes
4. On Sunday, Sam _ .
A. played the guitar
B. played on the computer
5. On Wednesday, Sam .
A. listened to music
B. watched TV
说出诊断佝偻病激期有哪些重要依据?