The doctor contemplated the difficult operation he had to perform.是什么意思？

The doctor contemplated the difficult operation he had to perform.

医生仔细地考虑他所要做的棘手的手术.

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

doctor

n. 医生，大夫，博士，神学家，医疗设备；vt.& vi. 医疗，行医；vt. 修理，装配，假造，搀杂，修改，修饰；

例句
A family doctor will be able to advise on suitable birth control.
家庭医生能够就合适的节育措施提出建议。

contemplated

v. 深思，细想，仔细考虑( contemplate的过去式 )，注视，凝视，考虑接受（发生某事的可能性），深思熟虑，沉思，苦思冥想；

例句
For a time he contemplated a career as an army medical doctor...
有段时间，他考虑去当军医。

difficult

adj. 困难的，难做的，难解的，不易相处的；

例句
It is a difficult job and they should be paid accordingly...
这是份棘手的工作，他们应得到相应的报酬。

operation

n. 操作，经营，手术，[数]运算，作用；

例句
...the operation a patient has had.
病人做过的手术

he

pron. 他，它，一个人；n. 雄性动物；

例句
Logic had prevailed and he had abandoned the idea.
最终理智占了上风，他打消了那个念头。

had

v. 有（ have的过去式和过去分词 ），（亲属关系中）接受，拿，买到；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

to

prep. 向，朝着，到，关于，属于；adv. 朝一个方向的，到某种状态，关闭；

例句
I suggest you leave it to an expert...
我建议你把它留给专家来解决。

perform

vt.& vi. 执行，履行，表演，扮演；vt. 工作，做，进行，完成；vi. 运行，表现，（驯兽）玩把戏；

例句
Any actor will tell you that it is easier to perform than to be themselves...
每一个演员都会告诉你演戏比做自己容易。