完成时：提示短语

  1. since的主句

    • It has been two years since I came to Maoming No.1 middle school.

  2. for+一段时间

    • For many years, people have dreamed of electric cars.

  3. in/over the last/past few/20 years

    • In the last few years thousands of films have been produced all over the world.

  4. 当一个受最高级形容词修饰的名词受到定语从句的修饰时,可用过去式、完成时

    • It is the best lecture that I have attended.

  5. up to now, so far迄今为止，already，yet

    • Up to now, the program have saved thousands of children.
    • I have finished 2 projects so far.

  6. It/This/That is the first time that... have/has done...这是第几次做

    • It is the first time that I have been to Beijing.
    • It was the first time that I had been to Beijing.

完成时：固定句式

  1. It/This/That is the first time that... have/has done...这是第几次做某事（现在）

    • It is the first time that I have been to Beijing.

  2. It/This/That was the first time that... had done...这是第几次做某事（过去）

    • It was the first time that I had been to Beijing.