I have been sick since yesterday.中have been 是什么是时态为什么要用been.

I have been sick since yesterday.中have been 是什么是时态为什么要用been. I have been busy since yesterday. have been是什么时态? have+been是什么时态 I have been busy yesterday afternoon为什么要用have been busy而不用ha have been working 是什么时态 have been doing是什么时态? have been to是什么时态? I have been successful是什么时态跟I have successed have been的时态. 英语中have been；has been是什么? The sick have been crued