python 字符串里的 % 格式化字符数量比后面给的变量多是什么意思？

下面的哪里错了？
x = "There are %d types of people." %10
binary = "binary"
do_not = "don't"
y = "Those who know %s and those who %s." % (binary,do_not)

print(x)
print(y)

print("I said %r." % x)
print("I also said: '%s'." % y)

joke_evaluation = "Isn't that ioke so funny!?"
hailarious = False

print(joke_evaluation % hailarious)

w = "This is the left side of..."
e = "a string with a right side."

print(w + e)

print(joke_evaluation % hailarious)

我不会~~~但还是要微笑~~~：）