have finished是什么時態(tài)

　　Once you have finished writing new code.

　　一旦你已經(jīng)完成了新代碼的編寫工作。

　　I have finished one fourth of my work now.

　　我現(xiàn)在已經(jīng)完成了我的四分子一的工作。

　　He should have finished the work by now.

　　到現(xiàn)在他應(yīng)該已經(jīng)做完那項工作了。