have experienced a经历了一个

have become a已成为

have not a stiver一文钱也没有

have to a certain拥有一定

have swallowed a dictionary爱使用深奥的字眼

have had a decreasing trend呈减少趋势

have given a theoretical account给出了理论解释

have only a general idea只知道个大概

have played a great role发挥了巨大作用

Rats have gnawed a hole老鼠咬了个洞