for i in range(1, 21, 2):
print(i, end=' ')
print("")
for a in range(3, 31):
if a % 3 == 0:
print(a)
或者
for i in range(1, 21, 2):
print(i, end=' ')
if i == 19:
print('')
for a in range(3, 31):
if a % 3 == 0:
print(a,)
换行可以用\n