细说python判断结构

a = 1

if a == 2:
    print("a is 2")

print("Progamed ended!")

a = 1
name = "Gorit"
if a == 2:
    print("a is 2")
    if name == "Gorit":
        print('My name is Gorit')

if a<5:
if a<=5:
if a>=5:
if a!+5:

a = 2
name = "Gorit"
if a == 2 and name == "Gorit":  #and相当于C语言种的&& 与操作，两个式子同为真时才为真
    print("a is 2")
    print('My name is Gorit')

a = 222
name = "Gorit"
if a == 2 or name == "Gorit": #逻辑或，相当于C语言当中的“||”，两者中有一个为真就是真
    print("a is 2")
    print('My name is Gorit')

score = int(input("input your English scores！:"))

if score >=90  and score <=100:
    print("A")

elif score >=80 and score <=89:
    print("B")

elif score >=70 and score <=79:
    print("C")

elif score <70:
    print("D")

另一种
score = int(input("input your English scores！:"))

if score >=90  and score <=100:
    grade = 'A'

elif score >=80 and score <=89:
    grade = 'B'

elif score >=70 and score <=79:
    grade = 'C'

else :
      grade = 'D'

print("Your grades is",grade)