if ... elif ... else ...

if condition_A:

   do thing_A

elif condition_B:

   do thing_B

else:

   do thing_C

while

while condition_A:

   do thing_A

for

for index in list:

   do thing_A

continue 和 break

continue 跳出当前本次循环；

break 跳出当前整个循环。