@@ -47,5 +47,7 @@ return function(dir, conf)
   load("Console")
   load("IO.File")
   load("Reflection.Assembly")
+  load("Threads.Timer")
+  load("Threads.Thread")
   load("Threads.Task")
 end
@@ -16,7 +16,7 @@ limitations under the License.
 
 local System = System
 local throw = System.throw
-local sr = System.sr
+local div = System.div
 local ArgumentOutOfRangeException = System.ArgumentOutOfRangeException
 local InvalidOperationException = System.InvalidOperationException
 local ArgumentNullException = System.ArgumentNullException
@@ -227,7 +227,7 @@ local function binarySearchArray(t, index, count, v, comparer)
   local lo = index
   local hi = index + count - 1
   while lo <= hi do
-    local i = lo + sr(hi - lo, 1)
+    local i = lo + div(hi - lo, 2)
     local order = compare(unWrap(t[i + 1]), v);
     if order == 0 then return i end
     if order < 0 then
@@ -278,7 +278,7 @@ local function findIndexOfArray(t, ...)
   for i = startIndex + 1, endIndex  do
     local item = unWrap(t[i])
     if match(item) then
-        return i - 1
+      return i - 1
     end
   end
   return -1
 
@@ -319,6 +319,7 @@ local timeZoneTicks = getTimeZone() * 1e7
 DateTime.BaseUtcOffset = TimeSpan(timeZoneTicks)
 
 local time = System.config.time or ostime
+System.time = time
 
 function DateTime.getUtcNow()
   local seconds = time()
 
@@ -16,7 +16,9 @@ limitations under the License.
 
 local System = System
 local throw = System.throw
+local try = System.try
 local trunc = System.trunc
+local post = System.post
 local Exception = System.Exception
 local NotImplementedException = System.NotImplementedException
 local ArgumentOutOfRangeException = System.ArgumentOutOfRangeException
@@ -134,13 +136,13 @@ function TaskExceptionHolder.__gc(this)
 end
 
 local Task = {}
-local taskIdCounter = 1
+local nextTaskId = 1
 local currentTask
 local completedTask
 
 local function getNewId()
-  local id = taskIdCounter
-  taskIdCounter = taskIdCounter + 1
+  local id = nextTaskId
+  nextTaskId = nextTaskId + 1
   return id
 end
 
@@ -167,12 +169,10 @@ function Task.getStatus(this)
 end
 
 local function getException(this)
-  local exceptionsHolder = this.exceptionsHolder
-  if exceptionsHolder then
-    return createExceptionObject(exceptionsHolder)
-  else
-    return nil
+  if this.status == TaskStatusFaulted then
+    return createExceptionObject(this.data)
   end
+  return nil
 end
 
 Task.getException = getException
@@ -193,7 +193,7 @@ function Task.getIsFaulted(this)
 end
 
 local function fromResult(result)
-  return setmetatable({ status = TaskStatusRanToCompletion, result = result }, Task)
+  return setmetatable({ status = TaskStatusRanToCompletion, data = result }, Task)
 end
 
 Task.FromResult = fromResult
@@ -202,7 +202,7 @@ local function fromCanceled(cancellationToken)
   if cancellationToken and cancellationToken:getIsCancellationRequested() then 
     throw(ArgumentOutOfRangeException("cancellationToken"))
   end
-  return setmetatable({ status = TaskStatusCanceled, cancellationToken = cancellationToken }, Task)
+  return setmetatable({ status = TaskStatusCanceled, data = cancellationToken }, Task)
 end
 
 Task.FromCanceled = fromCanceled
@@ -224,13 +224,7 @@ local function trySetComplete(this, status, data)
   end
 
   this.status = status
-  if status == TaskStatusRanToCompletion then
-    this.result = data
-  elseif status == TaskStatusFaulted then
-    this.exceptionsHolder = data
-  elseif status == TaskStatusCanceled then
-    this.cancellationToken = data
-  end
+  this.data = data
 
   local continueActions = this.continueActions
   if continueActions then
@@ -261,8 +255,9 @@ local function newWaitingTask(isVoid)
   return setmetatable({ status = TaskStatusWaitingForActivation, isVoid = isVoid }, Task)
 end
 
-local setTimeout = System.config.setTimeout
-local clearTimeout = System.config.clearTimeout
+local config = System.config
+local setTimeout = config.setTimeout
+local clearTimeout = config.clearTimeout
 
 function Task.Delay(delay, cancellationToken)
   if not setTimeout or not clearTimeout then
@@ -317,7 +312,22 @@ local function getContinueActions(task)
   return continueActions
 end
 
-function Task.ContinueWith(this, ...)
+function Task.ContinueWith(this, continuationAction)
+  local t = newWaitingTask()
+  local function f()
+    try(function ()
+      assert(trySetResult(t, continuationAction()))
+    end, function (e)
+      assert(trySetException(t, e))
+    end)
+  end
+  if isCompleted(this) then
+    post(f)
+  else
+    local continueActions = getContinueActions(task)
+    tinsert(continueActions, f)
+  end
+  return t
 end
 
 local function await(t, task)
@@ -327,9 +337,9 @@ local function await(t, task)
     local status = task.status
     local ok, v
     if status == TaskStatusRanToCompletion then
-      ok, v = true, task.result 
+      ok, v = true, task.data
     elseif status == TaskStatusFaulted then
-      ok, v = false, getException(task)
+      ok, v = false, createExceptionObject(task.data)
     elseif status == TaskStatusCanceled then
       ok, v = false, TaskCanceledException(task)
     else
@@ -353,9 +363,9 @@ function Task.await(this, task)
   if status == TaskStatusWaitingForActivation then
     return await(this, task)
   elseif status == TaskStatusRanToCompletion then
-    return task.result
+    return task.data
   elseif status == TaskStatusFaulted then
-    throw(getException(task))
+    throw(createExceptionObject(task.data))
   elseif status ==  TaskStatusCanceled then
     throw(TaskCanceledException(task))
   else
 
@@ -0,0 +1,135 @@
+--[[
+Copyright 2017 YANG Huan (sy.yanghuan@gmail.com).
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+--]]
+
+local System = System
+local throw = System.throw
+local trunc = System.trunc
+local Exception = System.Exception
+local ArgumentNullException = System.ArgumentNullException
+local ArgumentOutOfRangeException = System.ArgumentOutOfRangeException
+local NotSupportedException = System.NotSupportedException
+
+local type = type
+local setmetatable = setmetatable
+local coroutine = coroutine
+local ccreate = coroutine.create
+local cresume = coroutine.resume
+local cstatus = coroutine.status
+local cyield = coroutine.yield
+
+local ThreadStateException = System.define("System.ThreadStateException", {
+  __tostring = Exception.ToString,
+  __inherits__ = { Exception },
+
+  __ctor__ = function(this, message, innerException)
+     Exception.__ctor__(this, message or "Thread is running or terminated; it cannot restart.", innerException)
+  end
+})
+
+local Thread = {}
+local nextThreadId = 1
+local threadYield = {}
+
+local function getThreadId()
+  local id = nextThreadId
+  nextThreadId = nextThreadId + 1
+  return id
+end
+
+local mainThread = setmetatable({
+  id = getThreadId(),
+}, Thread)
+local currentThread = mainThread
+
+function Thread.getCurrentThread()
+  return currentThread
+end
+
+function Thread.__ctor__(this, start)
+  if start == nil then throw(ArgumentNullException("start")) end
+  this.start = start
+end
+
+function Thread.getIsAlive(this)
+  local co = this.co
+  return co and cstatus(co) ~= "dead"
+end
+
+function Thread.ManagedThreadId(this)
+  local id = this.id
+  if not id then
+    id = getThreadId()
+    this.id = id
+  end
+  return id
+end
+
+function Thread.Sleep(timeout)
+  if type(timeout) == "table" then
+    timeout = trunc(timeout:getTotalMilliseconds())
+    if timeout < -1 or timeout > 2147483647 then
+      throw(ArgumentOutOfRangeException("timeout"))
+    end
+  end
+  if currentThread == mainThread then
+    throw(NotSupportedException("mainThread not support"))
+  end
+  cyield(timeout)
+end
+
+function Thread.Yield()
+  if currentThread == mainThread then
+    return false
+  end
+  cyield(threadYield)
+  return true
+end
+
+Thread.IsBackground = false
+Thread.IsThreadPoolThread = false
+Thread.Priority = 2
+Thread.ApartmentState = 2
+
+local function run(t, obj)
+  post(function ()
+    currentThread = t
+    local ok, v = cresume(t.co, obj)
+    currentThread = mainThread
+    if ok then
+      if v == threadYield then
+        run(t)  
+      elseif v ~= nil then
+        if v ~= -1 then
+          
+        end
+      else   
+        t.co = false
+      end
+    else
+      print("Warning: Thread.Start" , e)
+    end  
+  end)
+end
+ 
+function Thread.start(this, parameter)
+  if this.co ~= nil then throw(ThreadStateException()) end
+  local co = ccreate(this.start)
+  this.co = co
+  this.start = nil
+  run(this, parameter)
+end
+
+System.define("System.Thread", Thread)