在SDH网同步结构中局内分配的同步网最高一级时钟称为（）。
参考答案：PRC基准时钟
请用括号中所给词的正确形式填空。
1. Marvin, you were walking _______(slow). Please walk more _______(quick).
2. Susie, you were reading a letter _______ (serious). Please read it _______ (sad).
3. Mary, you were setting the table too _______ (noisy). Please do it _______ (quiet).
4. Mike, you were bringing in the food _______ (casual). Please do it _______ (formal).
5. Am I speaking too _______ (fast)?
6. The weather was _______ (terrible) bad.
下列正确的是（）
A.适用两个样本均数t检验的资料，若用方差分析则效果更好
B.多个样本均数间的两两比较，可以将每两个样本分别比较作t检验
C.两组比较的方差分析的F值和t检验的t值有以下关系：F=t2
D.多组均数比较用方差分析得出差别有统计学意义后，只能用t检验作两两比较
E.方差分析只适合作两个以上均数的假设检验
(serious). Please read it _______ (sad).