钟形分布的特征是两头大、中间小。()
参考答案:错
As the years passed, many occasions—birthdays, awards, graduations — __________ with Dad’s flowers.
A.are marked
B.were marked
C.have marked
D.had marked
计算机网络的突出优点是()。
A.速度快
B.资源共享
C.精度高
D.容量大