The traditional pattern of classroom experience at the college level brings the professor and a group of 20 to 30 students together for a 45-to-50-minute class session two or three times a week.
大學課堂的傳統的教學方式是，一個教授和二三十名學生每周見面兩三次，每次授課時間45到50分鐘。
二. 人數用阿拉伯數字表示顯得更簡潔明了，但不定數量、近似值用單詞表示較恰當。
There are 203817 voters on the electoral rolls.
選舉名單上有203817個投票人。
Nearly thirty thousand voters took part in this election.
近3萬個投票人參加了這次選舉。
三. 遇到日期、百分比、帶單位的特殊數字，通常用阿拉伯數字。
Maximum swivel of table is l20.
工作臺的旋轉角度是120度。
3rd March 1991或3 March 1991;
a discount of 5 percent(5%的折扣);
eg. purchased 7 yards of carpet(買7碼地毯);
eg. ordered 2 pounds of minced steak(訂購2磅肉餡)
如果涉及的數目和單位是不定數，可用單詞表示。
eg. about five miles per hour(每小時大約5英里)
eg. at least ten yards away(至少有10碼遠)
eg. hesitated for a moment or two(猶豫了片刻)
eg. I have warned you a hundred times(我已經警告你多少遍了。)
四. 在科技文章中，數字頻繁出現，用阿拉伯數字比用單詞陳述更有利。
The new engine has a capacity of 4.3 litres and a power output of 153 kilowatts at 4400 revolutions per minute.
這臺新發動機的容積為4.3升，轉速為每分鐘4400轉，時輸出功率是153千瓦。
We know that the weight of a cubic foot of air at 0?C and 76cm，pressure is 0.08l pound, or 12 cubic feet of air weigh a pound.
