开机就蓝屏0x0000007b:什么时候使用现在完成时？

表示动作发生在过去，完成在过去，但强调与现在情况仍有联系，其结果或影响仍存在。现在完成时有一些标志性的时间状语： 考点一：for + 时间段；since + 时间点 They have lived in Beijing for five years. They have lived in Beijing since 1995. I have learned English for ten years. 考点二：常见的不确定的时间状语：lately; recently, just, already, yet, up to now; till now; so far, these days, Has it stopped raining yet ? 考点三：在表示“最近几世纪/ 年/ 月以来……”时间状语中，谓语动词用现在完成时。 in the past few years/months/weeks/days；over the past few years; during the last three months; for the last few centuries, through centuries; throughout history 等 考点四：表示“第几次做某事，”或在 “It is the best (worst, most interesting ) +名词 ＋that” 后面跟现在完成时。 This is my first time that I have visited China. This is the most interesting film I have ever seen. That is the only book that he has written.

表示动作发生在过去，完成在过去，但强调与现在情况仍有联系，其结果或影响仍存在。现在完成时有一些标志性的时间状语： 考点一：for + 时间段；since + 时间点 They have lived in Beijing for five years. They have lived in Beijing since 1995. I have learned English for ten years. 考点二：常见的不确定的时间状语：lately; recently, just, already, yet, up to now; till now; so far, these days, Has it stopped raining yet ? 考点三：在表示“最近几世纪/ 年/ 月以来……”时间状语中，谓语动词用现在完成时。 in the past few years/months/weeks/days；over the past few years; during the last three months; for the last few centuries, through centuries; throughout history 等 考点四：表示“第几次做某事，”或在 “It is the best (worst, most interesting ) +名词 ＋that” 后面跟现在完成时。 This is my first time that I have visited China. This is the most interesting film I have ever seen. That is the only book that he has written

since…… for+一段时间`

过去时就是过去做的事.
完成时有过去做的事对现在造成的影响.