A. He joined the League two years ago.

　　B.　He has been in the League for two years.

　　C. It is two years since he joined the League.

　　D. Two years has passed since he joined the League.

　　二、一般现在时与现在进行时的转换

　　在一般现在时中，at加上名词表示"处于某种状态"，如at work（在工作）, at school（上学、上课）等。此短语可与进行时态转换。请看：

　　Peter is at work, but Mike is at play.

　　Peter is working, but Mike is playing.

　　三、现在进行时与一般将来时的转换

　　在现在进行时态中go, come, leave, start, arrive等动词常与表示将来的时间状语连用表示将要发生的动作。如：I am coming, Mum! 意为"我就来，妈妈！"请看：

　　The train is leaving soon.

　　The train will leave soon.

　　四、"be going to+动词原形"与"will(shall)+动词原形"结构的转换

　　"be going to+动词原形"表示打算、计划要做的事；将来时"will(shall)+动词原形"结构在书面语中，当主语为第一人称时，常用助动词shall。在口语中，所有人称都可以用will。请看：

　　We are going to visit the Great Wall next Sunday.

　　We shall visit the Great Wall next Sunday.