知識點：字元串也有“加法和乘法”和print(i,end=’’)的使用
更多的練習，是為了打好基礎。開始吧！不要懶惰！不要複制粘貼！
在這節練習，我們複習了 {}.format() 和字元串的“加法”（第20、21行），新接觸了字元串的“乘法”（第4行）和第20行的print( i , end=’ ')
print("Mary had a little lamb.")
print("Its fleece was white as {}".format('snow'))
print("And everywhere that Mary went.")
print("." * 10) # what'd that do? 字元串的乘法是輸出10次的意思
end1 = "C"
end2 = "h"
end3 = "e"
end4 = "e"
end5 = "s"
end6 = "e"
end7 = "B"
end8 = "u"
end9 = "r"
end10 = "g"
end11 = "e"
end12 = "r"
# watch end = ' ' at the end. try removing it to see what happens
print(end1 + end2 + end3 + end4 + end5 + end6, end=' ')
print(end7 + end8 + end9 + end10 + end11 + end12)
print( i , end=’ ') ==>引号裡是一個空格，意思是輸入i後，以空格結尾。本來預設是換行。如果去掉end，則顯示如下結果
Cheese
Burger
What you should see
Mary had a little lamb.
Its fleece was white as snow
And everywhere that Mary went.
..........
Cheese Burger
Study Drills
1、 注釋每一行
2、 仔細看或讀每一行，找出你的錯誤
3、 從現在起，當你出錯了，在紙上寫你犯了什麼類型的錯誤
4、 當你要做下一個練習前，看看你犯過的錯誤，盡量不要再犯
5、 每個人都會犯錯。程式員經常犯錯。