Period / Full Stop (.) 句号、句点
  句号的写法，在英文里是个小黑点(.)，可在中文却是个小圈儿(。)(在科学技术文章里
也可用“小黑点”)。用法也有些差异，在英文方面，最“好玩”的是用在缩写方面：
* 句号用在陈述句、祈使句及礼貌问句等的句尾 * 句号用在缩写方面 * 句号用在数目字方面
3.1 句号用在陈述句、祈使句及礼貌问句等的句尾： 3.1.1 用在陈述句(Declarative sentence)尾，表示句子结束： 1. I am leaving now.
2. Ailan and Xiaodong are my friends.
3.1.2  用在祈使句(Imperative sentence)尾，表示句子结束： 1. Close the door.
2. Turn in your papers, please. 
3.1.3 用在礼貌的、祈使性的、以及间接疑问句(Interrogative sentence)尾，表示 句子结束：
1. Will you please send me three copies. 麻烦你给我三份。(不要看到Will
you...就在句尾加问号喔)
2. Since when am I supposed to believe this. 我什么时候会相信这个呢。
3. He asked if you can come. 他问你能不能来。
3.2 句号用在表示缩写(Abbreviation, Acronym):
3.2.1 缩写词(Abbreviation)：(将一个字词省略其中某些字母,字尾须加句号)
1. 称呼：Mr. = Mister, Mrs.= Misteress, Dr. = Doctor, Mim. = Ministor /
Ministry , Esq. = Esquire (先生) 2. 时间：yr. = year, min.=minute
3.  星期：Mon. = Monday, Tues. = Tuesday, Wed. = Wednesday, Thurs. =
Thursday, Fri. = Friday, Sat. = Saturday, Sun. = Sunday 4. 月份：Jan. = January, Feb. = February, Mar. = March, Apr. = April, Jun.
= June, Jul. = July, Aug./Ag. = August, Sept. = September, Oct. = October,
Nov. = November, Dec. = December (注意：oct. = octave八度, nov. = novelist
小说家, dec. = deceased亡故)
5. 国名：Afr. = Africa / African, Aus. = Austria / Austrian, Fr. = France
/ French, Ger. = Germany, It. = Italy / Italian
6.  其他：etc. = et cetera (等), Xmas. = Christmas, min. = minimum /
minor, max. = maximum, pc. = piece, Ltd. = Limited, num. =number / numbers (No. = Number 第几号之意)
3.2.2 Acronym (只取首字母的缩写词)：
1. 公元：A.D. = Anno Domin(公元)，B.C. = Before Christ(公元前)
2. 邮政：G.P.O. = General Post Office, C.O.D.= Cash on Delivery, P.O. /
p.o. = Postal Order, R.T.S. = Return To Sender
3, 时间：a.m. /A.M. = ante meridiem 上午， p.m. / P.M.= post meridiem下午
4. 国名：U.K. = United Kingdom, U.S.A. = United States of America
5. 其他：F.O.C. = Free Of Charge, R.I.P. = Rest In Peace 愿他安息, r.p.m.=
Revolution Per Minute, P.T.O. / p.t.o. = Please Turn Over 翻下页，P.T.A. =
Parent-Teachers' Association 家长教师协会
也许是大家觉得缩写词后加个小黑点是件麻烦事，因此有些就干脆省掉它，下面是一 些不加句点的缩写词：
1. 组织名：UN, UNESCO, WTO 2. 数目：$75 , 2nd , 5th , Henry V
3. 常用词：memo , math , exam , lab , dorm , TV , CD , VCD ,DVD,
PS =Postscript 附言，SARS (现在是无人不知其大名的了！) 4. 度量衡: mm , cm , km , g , mg , ml , kw , kv
3.3 句号用在数字方面： 3.3.1 表示小数点：
1. $12.50 , ￥200.20 , RM4.45, 50.45%, 5.2 kg
3.3.2 用于大纲列表： 例： I. 第一学期体育教学   1. 游泳     a. 自由式
注意：在括号内的数字或字母，不可加句号： (3), (b), (Iv)