如何使用continueWith继续一个任务和另一个任务?

    Dim listOfTask = New List(Of Task)
    For Each account In uniqueAccounts().Values
        Dim newtask = account.conditionalInitializeAsync()
        Dim nexttask = account.getPairsPriceStepAsync()
        listOfTask.Add(newtask)
        listOfTask.Add(nexttask)
        Dim nexttaskaftenewtask = newtask.ContinueWith(nexttask) 'compiler warning
    Next

        listOfTask.Add(newtask)
        listOfTask.Add(nexttask)

我想做什么

        listOfTask.Add(nexttaskaftenewtask )

我该怎么做?