diff --git a/json_test.go b/json_test.go
index be88920e..a06afae4 100644
--- a/json_test.go
+++ b/json_test.go
@@ -12,58 +12,29 @@ type Person struct {
 	Name string `json:"name"`
 	Age  int    `json:"age"`
 
-	Birthday1 Carbon `json:"birthday1" carbon:"layout:2006-01-02 15:04:05"`
-	Birthday2 Carbon `json:"birthday2" carbon:"layout:2006-01-02 15:04:05.999"`
-	Birthday3 Carbon `json:"birthday3" carbon:"layout:2006-01-02 15:04:05.999999"`
-	Birthday4 Carbon `json:"birthday4" carbon:"layout:2006-01-02 15:04:05.999999999"`
-
-	GraduatedAt1 Carbon `json:"graduated_at1" carbon:"layout:2006-01-02"`
-	GraduatedAt2 Carbon `json:"graduated_at2" carbon:"layout:2006-01-02.999"`
-	GraduatedAt3 Carbon `json:"graduated_at3" carbon:"layout:2006-01-02.999999"`
-	GraduatedAt4 Carbon `json:"graduated_at4" carbon:"layout:2006-01-02.999999999"`
-
-	OperatedAt1 Carbon `json:"operated_at1" carbon:"layout:15:04:05"`
-	OperatedAt2 Carbon `json:"operated_at2" carbon:"layout:15:04:05.999"`
-	OperatedAt3 Carbon `json:"operated_at3" carbon:"layout:15:04:05.999999"`
-	OperatedAt4 Carbon `json:"operated_at4" carbon:"layout:15:04:05.999999999"`
-
-	CreatedAt1 Carbon `json:"created_at1" carbon:"format:Y-m-d"`
-	CreatedAt2 Carbon `json:"created_at2" carbon:"format:H:i:s"`
-	CreatedAt3 Carbon `json:"created_at3" carbon:"format:Y-m-d H:i:s"`
-	CreatedAt4 Carbon `json:"created_at4"`
-}
+	Birthday0 Carbon `json:"birthday0"`
+
+	Birthday1 Carbon `json:"birthday1" carbon:"layout:2006-01-02"`
+	Birthday2 Carbon `json:"birthday2" carbon:"layout:15:04:05"`
+	Birthday3 Carbon `json:"birthday3" carbon:"layout:2006-01-02 15:04:05"`
 
-type Student struct {
-	Name     string `json:"name"`
-	Age      int    `json:"age"`
-	Birthday Carbon `json:"birthday"`
+	Birthday4 Carbon `json:"birthday4" carbon:"format:Y-m-d"`
+	Birthday5 Carbon `json:"birthday5" carbon:"format:H:i:s"`
+	Birthday6 Carbon `json:"birthday6" carbon:"format:Y-m-d H:i:s"`
 }
 
 func TestCarbon_MarshalJSON_LoadTag(t *testing.T) {
 	c := Parse("2020-08-05 13:14:15.999999999", PRC)
 	person := Person{
-		Name: "gouguoyin",
-		Age:  18,
-
+		Name:      "gouguoyin",
+		Age:       18,
+		Birthday0: c,
 		Birthday1: c,
 		Birthday2: c,
 		Birthday3: c,
 		Birthday4: c,
-
-		GraduatedAt1: c,
-		GraduatedAt2: c,
-		GraduatedAt3: c,
-		GraduatedAt4: c,
-
-		OperatedAt1: c,
-		OperatedAt2: c,
-		OperatedAt3: c,
-		OperatedAt4: c,
-
-		CreatedAt1: c,
-		CreatedAt2: c,
-		CreatedAt3: c,
-		CreatedAt4: c,
+		Birthday5: c,
+		Birthday6: c,
 	}
 
 	loadErr := LoadTag(&person)
@@ -72,64 +43,55 @@ func TestCarbon_MarshalJSON_LoadTag(t *testing.T) {
 	data, marshalErr := json.Marshal(&person)
 	assert.Nil(t, marshalErr)
 
-	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday1.String())
-	assert.Equal(t, "2020-08-05 13:14:15.999", person.Birthday2.String())
-	assert.Equal(t, "2020-08-05 13:14:15.999999", person.Birthday3.String())
-	assert.Equal(t, "2020-08-05 13:14:15.999999999", person.Birthday4.String())
-
-	assert.Equal(t, "2020-08-05", person.GraduatedAt1.String())
-	assert.Equal(t, "2020-08-05.999", person.GraduatedAt2.String())
-	assert.Equal(t, "2020-08-05.999999", person.GraduatedAt3.String())
-	assert.Equal(t, "2020-08-05.999999999", person.GraduatedAt4.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday0.String())
 
-	assert.Equal(t, "13:14:15", person.OperatedAt1.String())
-	assert.Equal(t, "13:14:15.999", person.OperatedAt2.String())
-	assert.Equal(t, "13:14:15.999999", person.OperatedAt3.String())
-	assert.Equal(t, "13:14:15.999999999", person.OperatedAt4.String())
+	assert.Equal(t, "2020-08-05", person.Birthday1.String())
+	assert.Equal(t, "13:14:15", person.Birthday2.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday3.String())
 
-	assert.Equal(t, "2020-08-05", person.CreatedAt1.String())
-	assert.Equal(t, "13:14:15", person.CreatedAt2.String())
-	assert.Equal(t, "2020-08-05 13:14:15", person.CreatedAt3.String())
-	assert.Equal(t, "2020-08-05 13:14:15", person.CreatedAt4.String())
+	assert.Equal(t, "2020-08-05", person.Birthday4.String())
+	assert.Equal(t, "13:14:15", person.Birthday5.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday6.String())
 
 	fmt.Printf("person output by json:\n%s\n", data)
 }
 
 func TestCarbon_MarshalJSON_UnLoadTag(t *testing.T) {
 	c := Parse("2020-08-05 13:14:15.999999999", PRC)
-	student := Student{
-		Name:     "gouguoyin",
-		Age:      18,
-		Birthday: c,
+	person := Person{
+		Name:      "gouguoyin",
+		Age:       18,
+		Birthday1: c,
+		Birthday2: c,
+		Birthday3: c,
+		Birthday4: c,
+		Birthday5: c,
+		Birthday6: c,
 	}
 
-	data, marshalErr := json.Marshal(&student)
+	data, marshalErr := json.Marshal(&person)
 	assert.Nil(t, marshalErr)
 
-	assert.Equal(t, "2020-08-05 13:14:15", student.Birthday.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday1.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday2.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday3.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday4.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday5.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday6.String())
 	fmt.Printf("student output by json:\n%s\n", data)
 }
 
 func TestCarbon_UnmarshalJSON_LoadTag(t *testing.T) {
 	str := `{
-		"name": "gouguoyin",
-		"age": 18,
-		"birthday1": "2020-08-05 13:14:15",
-		"birthday2": "2020-08-05 13:14:15.999",
-		"birthday3": "2020-08-05 13:14:15.999999",
-		"birthday4": "2020-08-05 13:14:15.999999999",
-		"graduated_at1": "2020-08-05",
-		"graduated_at2": "2020-08-05.999",
-		"graduated_at3": "2020-08-05.999999",
-		"graduated_at4": "2020-08-05.999999999",
-		"operated_at1": "13:14:15",
-		"operated_at2": "13:14:15.999",
-		"operated_at3": "13:14:15.999999",
-		"operated_at4": "13:14:15.999999999",
-		"created_at1": "2020-08-05",
-		"created_at2": "13:14:15",
-		"created_at3": "2020-08-05 13:14:15",
-		"created_at4": "2020-08-05 13:14:15"
+		"name":"gouguoyin",
+		"age":18,
+		"birthday0":"2020-08-05 13:14:15",
+		"birthday1":"2020-08-05",
+		"birthday2":"13:14:15",
+		"birthday3":"2020-08-05 13:14:15",
+		"birthday4":"2020-08-05",
+		"birthday5":"13:14:15",
+		"birthday6":"2020-08-05 13:14:15"
 	}`
 
 	var person Person
@@ -140,60 +102,51 @@ func TestCarbon_UnmarshalJSON_LoadTag(t *testing.T) {
 	unmarshalErr := json.Unmarshal([]byte(str), &person)
 	assert.Nil(t, unmarshalErr)
 
-	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday1.String())
-	assert.Equal(t, "2020-08-05 13:14:15.999", person.Birthday2.String())
-	assert.Equal(t, "2020-08-05 13:14:15.999999", person.Birthday3.String())
-	assert.Equal(t, "2020-08-05 13:14:15.999999999", person.Birthday4.String())
-
-	assert.Equal(t, "2020-08-05", person.GraduatedAt1.String())
-	assert.Equal(t, "2020-08-05.999", person.GraduatedAt2.String())
-	assert.Equal(t, "2020-08-05.999999", person.GraduatedAt3.String())
-	assert.Equal(t, "2020-08-05.999999999", person.GraduatedAt4.String())
-
-	assert.Equal(t, "13:14:15", person.OperatedAt1.String())
-	assert.Equal(t, "13:14:15.999", person.OperatedAt2.String())
-	assert.Equal(t, "13:14:15.999999", person.OperatedAt3.String())
-	assert.Equal(t, "13:14:15.999999999", person.OperatedAt4.String())
-
-	assert.Equal(t, "2020-08-05", person.CreatedAt1.String())
-	assert.Equal(t, "13:14:15", person.CreatedAt2.String())
-	assert.Equal(t, "2020-08-05 13:14:15", person.CreatedAt3.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday0.String())
+	assert.Equal(t, "2020-08-05", person.Birthday1.String())
+	assert.Equal(t, "13:14:15", person.Birthday2.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday3.String())
+	assert.Equal(t, "2020-08-05", person.Birthday4.String())
+	assert.Equal(t, "13:14:15", person.Birthday5.String())
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday6.String())
 
 	fmt.Printf("Json string parse to person:\n%+v\n", person)
 }
 
 func TestCarbon_UnmarshalJSON_UnLoadTag(t *testing.T) {
 	str := `{
-		"name": "gouguoyin",
-		"age": 18,
-		"birthday": "2020-08-05 13:14:15.999"
+		"name":"gouguoyin",
+		"age":18,
+		"birthday0":"2020-08-05 13:14:15",
+		"birthday1":"2020-08-05"
 	}`
 
-	var student Student
-	unmarshalErr := json.Unmarshal([]byte(str), &student)
+	var person Person
+	unmarshalErr := json.Unmarshal([]byte(str), &person)
 	assert.Nil(t, unmarshalErr)
 
-	assert.Equal(t, "2020-08-05 13:14:15", student.Birthday.String())
-	fmt.Printf("Json string parse to student:\n%+v\n", student)
+	assert.Equal(t, "2020-08-05 13:14:15", person.Birthday0.String())
+	assert.Equal(t, "2020-08-05 00:00:00", person.Birthday1.String())
+	fmt.Printf("Json string parse to person:\n%+v\n", person)
 }
 
 func TestError_JSON(t *testing.T) {
-	student := Student{
-		Name:     "gouguoyin",
-		Age:      18,
-		Birthday: Parse("XXX"),
+	person := Person{
+		Name:      "gouguoyin",
+		Age:       18,
+		Birthday1: Parse("XXX"),
 	}
 
-	_, marshalErr := json.Marshal(student)
-	fmt.Println("marshal error", marshalErr.Error())
+	_, marshalErr := json.Marshal(person)
+	fmt.Println("marshal error:", marshalErr.Error())
 	assert.NotNil(t, marshalErr)
 
 	str := `{
 		"name": "gouguoyin",
 		"age": 18,
-		"birthday": "2020-08-05 13:14:15.999"
+		"birthday1": "2020-08-05 13:14:15"
 	}`
-	unmarshalErr := json.Unmarshal([]byte(str), &student)
-	fmt.Println("unmarshal error", unmarshalErr.Error())
+	unmarshalErr := json.Unmarshal([]byte(str), &person)
+	fmt.Println("unmarshal error:", unmarshalErr.Error())
 	assert.NotNil(t, unmarshalErr)
 }