在“We like maths”这个句子的所有字母中，字母“e”出现的频率约为______（结果保留两位有效数字）；若2x³y^m与-xⁿy²是同类项，则m+n=______．

How long has the man been a party member

A. Two years.

B. One year.


C. Less than a year.