2、import 用來引入模塊
比如引入sys模塊，查看當前python的全局環境變量

import sys
print(sys.path)

3、判斷語句
if elif else 後面以冒號結尾連接下一行 嚴格的縮進（4個空格）
幾個例子：

###guess age
counter = 0
age = 28
for i in range(10):
    if counter < 3:
        print("------>counter",counter)
        guess_num = int(input("input your guess num:"))
        if guess_num == age :
            print("Congratulations! you get it!")
            break
        elif guess_num > age:
            print("think smaller!")
        else:
            print("think big!")
    else:
        continue_confirm = input("Do you want to continue play?")
        if continue_confirm == ‘yes‘:
            counter = 0
            continue
        else:
            print("bye")
            break
    counter += 1
 

s13day1第一堂課