EX30

 1 people = 30
 2 cars = 40
 3 buses = 15
 4 
 5 if cars > people:
 6     print "We should take the cars."
 7 elif cars < people:
 8     print "We should not take the cars."
 9 else:
10     print "We can‘t decide."
11 
12 if buses > cars:
13     print "That‘s too many buses."
14 elif buses < cars:
15     print "Maybe we chould take the buses."
16 else:
17     print "We still can‘t decide."
18     
19 if people > buses:
20     print "Alright, let‘s just take the buses."
21 else:
22     print "Fine, let‘s stay home then."

1 num = 0
2 if num > 0 :
3     print ‘这个数比0大‘
4 elif num < 0 :
5     print ‘这个数比0小‘
6 else :
7     print ‘这个数是0‘