score=70
if score >= 90:
  print("A")
elif score >= 60:
  print("B")
else:
  print("C")

def getLevel(score):
  if score >= 90: return "A"
  elif score >= 60: return "B"
  else: return "C"

sum = 0
i = 0
while i <= 10:
  sum = sum + i
  i = i + 1

sum = 0
i = 0
while i <= 3:
  sum = sum + i
  i = i + 1
else:
  print(f"done,i={i}")


pets = ["cat","dog","tiger"]
for i in pets:
  print(i)


for i in range(3):
  print(i,end=" ")

for i in range(1,5):
  print(i,end=" ")

for i in range(1,10,3):
  print(i,end=" ")


pets = ["cat","dog","tiger"]
for i in range(len(pets)):
  print(i,pets[i])


list(range(3))



pass 不做任何事情，一般用做占位语句