def check_even_exists(arr):
for num in arr:
if num % 2 == 0: # 如果是偶数,返回True
return True
return False # 如果所有数字都是奇数,返回False
# 示例
print(check_even_exists([1, 3, 5, 7, 9])) # False
print(check_even_exists([2, 4, 6, 8, 10])) # True
print(check_even_exists([1, 2, 3, 4, 5])) # True