现在完成时由助动词have的现在式加上动词的过去分词构成,它跨在两个时间之上,一个是过去,一个是现在,也就是说,它的动作发生在过去,但是它对现在有影响或结果,而这种影响或结果却往往是说话人的兴趣所在,所以后面可以不用时间状语.现在完成时表示的动作离说话人的说话时刻可近可远.如：
The car has arrived.
Someone has broken the window.
He's been sick.
He has traveled over a lot of lands.
She has had a good education.
I have been a teacher.
有时可以连用现在完成时表示一个以上相互紧接的动作.
They have gone to the moon and come back to earth again.
I have bought a pen but lost it.
She's been married and divorced.
注意,have been和have gone的意思不一样,如：
I have been to the library.这里,have been表示“去而复归”.如果表示“去而未回”则要用have gone,并且have gone只用于第三人称,如：
He has gone to the library.
I am the only one who has gone to a public high school.（have gone to后接学校,表示“上过学”）
have been可以和动词不定式连用,如：
I have been to see John.
在美国口语中,get的过去分词为gotten,所以get的现在完成时为have gotten,如：
Tom,I have gotten some very good news for you.
你给出的句子,主语是第一人称,表示“去而复归”的含义,所以用have been.这句话的意思是：“劳拉,你要去银行吗?不,我已经去过银行了.”希望我能帮助你解疑释惑.