一个英语句子看不懂语法he accepted their mistaken estimate of his ability, felt that is was useless to try,and was very poor at arithmetic, just as they expected. 特别是felt that is was useless to try看不懂,请帮忙分析一下结构.谢谢

应该是felt that it was...吧
he是句子的主语，accepted、felt和was poor是句子的谓语，felt后面的that是宾语从句的引导词
后面的just...是句子的状语，意思是就像他们所料想的那样
整句话的意思：他接受了他们对他的能力的错误评估，觉得尝试是没有用的，就像他们所料想的那样，他对算术几乎一无所知。
大概就是这样啦，看得懂么？

这个句子三个动词是并列地位的
accepted,felt,was
都做谓语
as the expected 是状语
正如他们期盼的一样，他接受了对于他能力错误的评估，感到尝试也没有，他的数学实在是很差

he accepted their mistaken estimaate of his ability ,(he )felt that it was useless to try , and (he )was poor at arithmetic, just as they expected. 那个is 肯定是 it

felt 后面的that is was useless to try是felt的宾语，是个句子。
觉得尝试没用。

不好意思,前几天只是看了一眼问题就匆匆回复了,回答的有些草率.
但我说此句引导词"that"后面缺主语并没有问题.只不过当时没有注意LZ多打了一个"Be"动词.为什么说"that"后面缺主语,因为"felt"后面是"that"引导的宾语从句,引导词"that"在宾语从句中不作任何成分,也无任何意义,只起引导词的作用,所以that后面必缺主语成分
此句涉及到并列句中的省略问题:
语法规则:在并列句中,相同的成分如主语,谓语,宾语等都可以省略：
此句因为有两个以上的并列关系子句,所以把并列连词"and"放到了最后.
三个并列句中的谓语"accepted,felt,was" ,由于他们的主语相同都是"He"
为避免重复,后两个省略掉了.
对于LZ的问题补充:"felt that "主语" was useless to try"
此句只是省略主语"He"的并列句.如果让此句做状语,那应该把"felt"改成
"feeling"
If you still feel confused ,leave a message please

整句话的意思：他接受了他们对他的能力的错误评估，觉得尝试是没有用的，就像他们所料想的那样，他对算术几乎一无所知。
其中accepted their mistaken estimate of his ability,felt that is was useless to try和was very poor at arithmetic,这三句话都是谓语 ，just as they expected. 是插入语。在felt that is was useless to try中 that is 也是一个插入语，表示强调的意思：也就是...。
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