现在完成时和过去完成时专项练习（句型转换），包含了三种题型：汉译英，延续动词和非待续动词之间的转化，句型变化，更有利于学生多方面的掌握这个语法！内附答案。

现在完成时和过去完成时专项练习（句型）
一、句型转换
1．I had sold the ticket when she came.（改否定句）
2.She had sung a song to us before she danced.（改否定句）
3.They began to climbed the mountain after they had bought all the food and drink.（否定句）
4.By 10:00 a.m, I had been very hungry. （改一般疑问）
5.Lucy had already completed the project when I arrived.（改一般疑问）
6.By the time he got to the airport, the plane had taken off. （改一般疑问）