致学生 v 致老师 v Thanks vi 练习序号 页码 110 现在进行时与一般现在时 2 (I am doing and I do) 1117 一般过去时与过去进行时 7 (I did and I was doing) 1822 现在时与过去时 11 (I do / I am doing and I did / I was doing) 2328 现在完成时 / 现在完成进行时 14 (I have done and I have been doing) 2930 现在完成时 / 现在完成进行时与一般过去时 18 (I have done and I have been doing; I did) 3134 现在完成时 / 现在完成进行时与现在时 19 (I have done / I have been doing and I do / I am doing) 3536 现在完成时 / 现在完成进行时、现在时与一般过去时 22 (I have done / I have been doing, I do / I am doing and I did) 3742 现在完成时 / 现在完成进行时与一般过去时 23 (I have done / I have been doing and I did) 4346 一般过去时、过去进行时与过去完成时 / 过去完成进行时 27 (I did, I was doing and I had done / I had been doing) ................