請問大大們，如題
1.await是否代表等待非同步執行完才會執行下一段呢？
2.如果await是否代表等待非同步執行完才會執行下一段，那這樣的話跟同步的程式有何差別？
下面第一段程式註解看起來是這個意思，但也看了其它async/await的文章，有些感覺await關鍵字並不是用來表示需等待非同步執行完才會執行下一段的意思，只是一個呼叫非同步方法的一個關鍵字。
上來再三確認一下await是否代表呼叫非同步執行同時也需等待非同步執行完才會執行下一段呢～

private async void btnThread6_Click(object sender, EventArgs e)
{
    //Task<int> measn it will return an it when finish the Task.
    //This Task<int> task is actually pointing to SlowFunc() function
    Task<int> task = new Task<int>(SlowFunc);
    task.Start();
    lbl1.Text = "Processing...";
    //.Net will use some special algorism to avoid blocking and
    //Wait until the SlowFunc() task completes.
    int outputInt = await task;
    lbl1.Text = $"outputInt=={outputInt}";
}

這裡的await是否也代表等待first執行完才會執行下一段second呢？

// Serial execution
public async Task<List<Thing>> GetThings()
{
    var first = await GetExpensiveThing();
    var second = await GetExpensiveThing();
    return new List<Thing>() { first, second };
}

以下這段taskA.Wait();感覺才是等待非同步執行完才會執行下一段

public static void Main()
{
  Thread.CurrentThread.Name = "Main";
  // Define and run the task.
  Task taskA = Task.Run( () => Console.WriteLine("Hello from taskA."));
  // Output a message from the calling thread.
  Console.WriteLine("Hello from thread '{0}'.",
                      Thread.CurrentThread.Name);
  taskA.Wait();
}

以下這段theTask.Result;也可以用來等待非同步執行完才會執行下一段

static string DownloadSource(string url)
{
    using (HttpClient httpClient = new HttpClient())
    {
        Console.WriteLine($"Getting source for {url}");
        Task<string> theTask = httpClient.GetStringAsync(url);
        string source = theTask.Result;
        Console.WriteLine($"Finished getting source for {url}");
        return source;
    }
}

Task.WaitAll;也可以用來等待非同步執行完才會執行下一段

void Main()
{
	var task1 = Task.Run(() => Task1());
	var task2 = Task.Run(() => Task2());
	var task3 = Task.Run(() => Task3());
	Task.WaitAll(task1,task2,task3); //在此等待所有任務結果，才繼續往下執行
	Console.WriteLine("completed task");
}

另外請教
Task 是屬於非同步
Parallel 是屬於多執行緒
以上認知不知是否正確？

Parallel範例

static void Main(string[] args)
{
    var sw = new Stopwatch();
    sw.Start();
    const int numParts = 10;
    var primes = new List<int>[numParts];
    Parallel.For(0, numParts, i => primes[i] = GetPrimeNumbers(i == 0 ? 2 : i * 1000000 + 1, (i + 1) * 1000000));
    var result = primes.Sum(p => p.Count);
    Console.WriteLine("Total prime numbers: {0}\nProcess time: {1}", result, sw.ElapsedMilliseconds);
}