对时点指标特点叙述不正确的是( )。
A.只能间断计数
B.各时点指标不可以直接累加
C.每个时点指标值的大小与时间长短无关
D.计数的准确率低
参考答案:D
Though ____ many times, the song still sounds as nice as before. [ ]
A. it was heard
B. hearing
C. heard
D. to be heard
牛仔服装非水洗产品胸围允许偏差()cm。
A.±1
B.±0.8
C.±1.5
D.±2