diff --git "a/Lesson-3/assignment/56_\350\203\241\351\227\260\347\245\272_\347\254\254\344\270\211\346\254\241\344\275\234\344\270\232.sol" "b/Lesson-3/assignment/56_\350\203\241\351\227\260\347\245\272_\347\254\254\344\270\211\346\254\241\344\275\234\344\270\232.sol"
new file mode 100644
index 0000000..a04235a
--- /dev/null
+++ "b/Lesson-3/assignment/56_\350\203\241\351\227\260\347\245\272_\347\254\254\344\270\211\346\254\241\344\275\234\344\270\232.sol"
@@ -0,0 +1,140 @@
+/*作业请提交在这个目录下*/
+
+/*作业请提交在这个目录下*/
+
+############################################## Codes for Question 1. and Question 2. #########################################
+
+pragma solidity ^0.4.14;
+
+contract Payroll {
+    
+    struct Employee {
+        address EmployeeAddress;
+        uint salary;
+        uint lastPayday;
+    }
+
+    mapping(address => Employee) public employees;
+
+    uint constant payDuration = 30 seconds;
+    
+    address OwnerAddress;
+    
+    uint totalSalary = 0;
+    
+    address thisAddress = this;  
+   
+    function Payroll() public {
+        OwnerAddress = msg.sender;
+    }
+    
+    modifier onlyOwner() {
+        require(msg.sender == OwnerAddress);
+        _;
+    }
+    
+    modifier employeeExist(address curr_EmployeeAddress) {
+        
+        var curr_employee = employees[curr_EmployeeAddress];
+        assert(curr_employee.EmployeeAddress != 0x0);
+        _;
+        
+    }
+    
+    function addEmployee(address curr_EmployeeAddress, uint curr_salary) onlyOwner {
+    
+        assert(employees[curr_EmployeeAddress].EmployeeAddress == 0x0);
+        
+        uint unitSalary = curr_salary * 1 ether;
+        employees[curr_EmployeeAddress] = Employee(curr_EmployeeAddress, unitSalary, now);
+        
+        totalSalary += unitSalary;
+        
+    }
+    
+    modifier partialPay(address curr_EmployeeAddress) {
+    
+        _partialPay(employees[curr_EmployeeAddress]);
+        _;
+        
+    }
+    function _partialPay(Employee employee) private {
+    
+        uint tempSalary = employee.salary * (now - employee.lastPayday);
+        tempSalary = tempSalary / payDuration;
+        
+        employee.EmployeeAddress.transfer(tempSalary);
+        
+    }
+    
+    
+   function removeEmployee(address curr_EmployeeAddress) onlyOwner employeeExist(curr_EmployeeAddress) partialPay(curr_EmployeeAddress) {
+        
+        var curr_employee = employees[curr_EmployeeAddress];
+        totalSalary -= curr_employee.salary;
+        
+        delete employees[curr_EmployeeAddress];
+        
+    }
+    
+    function updateEmployee(address curr_EmployeeAddress, uint new_salary) onlyOwner employeeExist(curr_EmployeeAddress) partialPay(curr_EmployeeAddress) {
+        
+        var curr_employee = employees[curr_EmployeeAddress];
+        
+        uint unitSalary = new_salary * 1 ether;
+        totalSalary = totalSalary - curr_employee.salary + unitSalary;
+
+        curr_employee.salary = unitSalary;
+        curr_employee.lastPayday = now;
+        
+    }
+    
+    function changePaymentAddress(address curr_EmployeeAddress, address new_EmployeeAddress) onlyOwner employeeExist(curr_EmployeeAddress) partialPay(curr_EmployeeAddress) {
+        
+        var curr_employee = employees[curr_EmployeeAddress];
+        
+        curr_employee.EmployeeAddress = new_EmployeeAddress;
+        
+    }
+
+    function addFund() payable public returns (uint)  {
+    
+        return thisAddress.balance;
+        
+    }
+    
+    function calculateRunway() public view returns (uint) {
+    
+        return thisAddress.balance / totalSalary;
+        
+    }
+    
+    function hasEnoughFund() public view returns (bool) {
+    
+        return calculateRunway() > 0;
+        
+    }
+    
+    function getPaid() employeeExist(msg.sender){
+    
+        var curr_employee = employees[msg.sender];
+        
+        var newPayday = curr_employee.lastPayday + payDuration;
+        assert(newPayday < now);
+        
+        curr_employee.lastPayday = newPayday;
+        curr_employee.EmployeeAddress.transfer(curr_employee.salary);
+        
+    }    
+}
+
+################################################### Snapshots for Question 1. ##############################################
+### attached ###
+
+######################################################### Question 3. ######################################################
+
+       |-----> B-----|
+       |             |------> K1------|
+O ---->|-----> A--|--|                |-----> Z
+       |          |---------> K2------|
+       |-----> C--|
diff --git "a/Lesson-3/assignment/56_\350\203\241\351\227\260\347\245\272_\347\254\254\344\270\211\346\254\241\344\275\234\344\270\232Q1\346\210\252\345\233\276.zip" "b/Lesson-3/assignment/56_\350\203\241\351\227\260\347\245\272_\347\254\254\344\270\211\346\254\241\344\275\234\344\270\232Q1\346\210\252\345\233\276.zip"
new file mode 100644
index 0000000..ac38c40
Binary files /dev/null and "b/Lesson-3/assignment/56_\350\203\241\351\227\260\347\245\272_\347\254\254\344\270\211\346\254\241\344\275\234\344\270\232Q1\346\210\252\345\233\276.zip" differ
diff --git a/Lesson-3/assignment/yours.sol b/Lesson-3/assignment/yours.sol
deleted file mode 100644
index dfdb2c4..0000000
--- a/Lesson-3/assignment/yours.sol
+++ /dev/null
@@ -1 +0,0 @@
-/*作业请提交在这个目录下*/
diff --git "a/Lesson-5/assignment/56_\350\203\241\351\227\260\347\245\272_\347\254\254\344\272\224\346\254\241\344\275\234\344\270\232.zip" "b/Lesson-5/assignment/56_\350\203\241\351\227\260\347\245\272_\347\254\254\344\272\224\346\254\241\344\275\234\344\270\232.zip"
new file mode 100644
index 0000000..b2aed11
Binary files /dev/null and "b/Lesson-5/assignment/56_\350\203\241\351\227\260\347\245\272_\347\254\254\344\272\224\346\254\241\344\275\234\344\270\232.zip" differ