A series of mischance happened.
一连串不幸的事情发生了
The student always asks his teacher a series of questions.
这个学生总是问他老师一连串的问题.
He drew a series of parallel lines.
他画了一组平行线.
Then began a series of experiments.
然后一系列的实验开始了.
You don't need to a series of notes.
你不需要把一系列的笔记都写下来.